Update time zone data files to tzdata release 2017b.

DST law changes in Chile, Haiti, and Mongolia.  Historical corrections for
Ecuador, Kazakhstan, Liberia, and Spain.

The IANA crew continue their campaign to replace invented time zone
abbrevations with numeric GMT offsets.  This update changes numerous zones
in South America, the Pacific and Indian oceans, and some Asian and Middle
Eastern zones.  I kept these abbreviations in the tznames/ data files,
however, so that we will still accept them for input.  (We may want to
start trimming those files someday, but I think we should wait for the
upstream dust to settle before deciding what to do.)

In passing, add MESZ (Mitteleuropaeische Sommerzeit) to the tznames lists;
since we accept MEZ (Mitteleuropaeische Zeit) it seems rather strange not
to take the other one.  And fix some incorrect, or at least obsolete,
comments that certain abbreviations are not traceable to the IANA data.

src/timezone/data/africa

@@ -6,15 +6,15 @@
 # tz@iana.org for general use in the future).  For more, please see
 # the file CONTRIBUTING in the tz distribution.
 
-# From Paul Eggert (2014-10-31):
+# From Paul Eggert (2017-02-20):
 #
 # Unless otherwise specified, the source for data through 1990 is:
 # Thomas G. Shanks and Rique Pottenger, The International Atlas (6th edition),
 # San Diego: ACS Publications, Inc. (2003).
 # Unfortunately this book contains many errors and cites no sources.
 #
-# Gwillim Law writes that a good source
-# for recent time zone data is the International Air Transport
+# Many years ago Gwillim Law wrote that a good source
+# for time zone data was the International Air Transport
 # Association's Standard Schedules Information Manual (IATA SSIM),
 # published semiannually.  Law sent in several helpful summaries
 # of the IATA's data after 1990.  Except where otherwise noted,
@@ -31,39 +31,33 @@
 # A reliable and entertaining source about time zones is
 # Derek Howse, Greenwich time and longitude, Philip Wilson Publishers (1997).
 #
+# European-style abbreviations are commonly used along the Mediterranean.
+# For sub-Saharan Africa abbreviations were less standardized.
 # Previous editions of this database used WAT, CAT, SAT, and EAT
-# for +0:00 through +3:00, respectively,
-# but Mark R V Murray reports that
-# 'SAST' is the official abbreviation for +2:00 in the country of South Africa,
-# 'CAT' is commonly used for +2:00 in countries north of South Africa, and
-# 'WAT' is probably the best name for +1:00, as the common phrase for
+# for UT +00 through +03, respectively,
+# but in 1997 Mark R V Murray reported that
+# 'SAST' is the official abbreviation for +02 in the country of South Africa,
+# 'CAT' is commonly used for +02 in countries north of South Africa, and
+# 'WAT' is probably the best name for +01, as the common phrase for
 # the area that includes Nigeria is "West Africa".
-# He has heard of "Western Sahara Time" for +0:00 but can find no reference.
-#
-# To make things confusing, 'WAT' seems to have been used for -1:00 long ago;
-# I'd guess that this was because people needed _some_ name for -1:00,
-# and at the time, far west Africa was the only major land area in -1:00.
-# This usage is now obsolete, as the last use of -1:00 on the African
-# mainland seems to have been 1976 in Western Sahara.
-#
-# To summarize, the following abbreviations seem to have some currency:
-#	-1:00	WAT	West Africa Time (no longer used)
-#	 0:00	GMT	Greenwich Mean Time
-#	 2:00	CAT	Central Africa Time
-#	 2:00	SAST	South Africa Standard Time
-# and Murray suggests the following abbreviation:
-#	 1:00	WAT	West Africa Time
-# I realize that this leads to 'WAT' being used for both -1:00 and 1:00
-# for times before 1976, but this is the best I can think of
-# until we get more information.
+#
+# To summarize, the following abbreviations seemed to have some currency:
+#	 +00	GMT	Greenwich Mean Time
+#	 +02	CAT	Central Africa Time
+#	 +02	SAST	South Africa Standard Time
+# and Murray suggested the following abbreviation:
+#	 +01	WAT	West Africa Time
+# Murray's suggestion seems to have caught on in news reports and the like.
+# I vaguely recall 'WAT' also being used for -01 in the past but
+# cannot now come up with solid citations.
 #
 # I invented the following abbreviations; corrections are welcome!
-#	 2:00	WAST	West Africa Summer Time
-#	 2:30	BEAT	British East Africa Time (no longer used)
-#	 2:45	BEAUT	British East Africa Unified Time (no longer used)
-#	 3:00	CAST	Central Africa Summer Time (no longer used)
-#	 3:00	SAST	South Africa Summer Time (no longer used)
-#	 3:00	EAT	East Africa Time
+#	 +02	WAST	West Africa Summer Time
+#	 +03	CAST	Central Africa Summer Time (no longer used)
+#	 +03	SAST	South Africa Summer Time (no longer used)
+#	 +03	EAT	East Africa Time
+# 'EAT' also seems to have caught on; the others are rare but are paired
+# with better-attested non-DST abbreviations.
 
 # Algeria
 # Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
@@ -121,17 +115,17 @@ Zone	Africa/Algiers	0:12:12 -	LMT	1891 Mar 15  0:01
 
 # Cape Verde / Cabo Verde
 #
-# Shanks gives 1907 for the transition to CVT.
+# Shanks gives 1907 for the transition to +02.
 # Perhaps the 1911-05-26 Portuguese decree
-# http://dre.pt/pdf1sdip/1911/05/12500/23132313.pdf
+# https://dre.pt/pdf1sdip/1911/05/12500/23132313.pdf
 # merely made it official?
 #
 # Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
 Zone Atlantic/Cape_Verde -1:34:04 -	LMT	1907        # Praia
-			-2:00	-	CVT	1942 Sep
-			-2:00	1:00	CVST	1945 Oct 15
-			-2:00	-	CVT	1975 Nov 25  2:00
-			-1:00	-	CVT
+			-2:00	-	-02	1942 Sep
+			-2:00	1:00	-01	1945 Oct 15
+			-2:00	-	-02	1975 Nov 25  2:00
+			-1:00	-	-01
 
 # Central African Republic
 # See Africa/Lagos.
@@ -388,7 +382,7 @@ Rule	Ghana	1920	1942	-	Sep	 1	0:00	0:20	GHST
 Rule	Ghana	1920	1942	-	Dec	31	0:00	0	GMT
 # Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
 Zone	Africa/Accra	-0:00:52 -	LMT	1918
-			 0:00	Ghana	%s
+			 0:00	Ghana	GMT/+0020
 
 # Guinea
 # See Africa/Abidjan.
@@ -397,20 +391,20 @@ Zone	Africa/Accra	-0:00:52 -	LMT	1918
 #
 # Shanks gives 1911-05-26 for the transition to WAT,
 # evidently confusing the date of the Portuguese decree
-# http://dre.pt/pdf1sdip/1911/05/12500/23132313.pdf
+# https://dre.pt/pdf1sdip/1911/05/12500/23132313.pdf
 # with the date that it took effect, namely 1912-01-01.
 #
 # Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
 Zone	Africa/Bissau	-1:02:20 -	LMT	1912 Jan  1
-			-1:00	-	WAT	1975
+			-1:00	-	-01	1975
 			 0:00	-	GMT
 
 # Kenya
 # Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
 Zone	Africa/Nairobi	2:27:16	-	LMT	1928 Jul
 			3:00	-	EAT	1930
-			2:30	-	BEAT	1940
-			2:45	-	BEAUT	1960
+			2:30	-	+0230	1940
+			2:45	-	+0245	1960
 			3:00	-	EAT
 Link Africa/Nairobi Africa/Addis_Ababa	 # Ethiopia
 Link Africa/Nairobi Africa/Asmara	 # Eritrea
@@ -426,18 +420,25 @@ Link Africa/Nairobi Indian/Mayotte
 # See Africa/Johannesburg.
 
 # Liberia
-# From Paul Eggert (2006-03-22):
-# In 1972 Liberia was the last country to switch
-# from a UTC offset that was not a multiple of 15 or 20 minutes.
-# Howse reports that it was in honor of their president's birthday.
-# Shank & Pottenger report the date as May 1, whereas Howse reports Jan;
-# go with Shanks & Pottenger.
-# For Liberia before 1972, Shanks & Pottenger report -0:44, whereas Howse and
-# Whitman each report -0:44:30; go with the more precise figure.
+#
+# From Paul Eggert (2017-03-02):
+#
+# The Nautical Almanac for the Year 1970, p 264, is the source for -0:44:30.
+#
+# In 1972 Liberia was the last country to switch from a UTC offset
+# that was not a multiple of 15 or 20 minutes.  The 1972 change was on
+# 1972-01-07, according to an entry dated 1972-01-04 on p 330 of:
+# Presidential Papers: First year of the administration of
+# President William R. Tolbert, Jr., July 23, 1971-July 31, 1972.
+# Monrovia: Executive Mansion.
+#
+# Use the abbreviation "MMT" before 1972, as the more-accurate numeric
+# abbreviation "-004430" would be one byte over the POSIX limit.
+#
 # Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
 Zone	Africa/Monrovia	-0:43:08 -	LMT	1882
 			-0:43:08 -	MMT	1919 Mar # Monrovia Mean Time
-			-0:44:30 -	LRT	1972 May # Liberia Time
+			-0:44:30 -	MMT	1972 Jan 7 # approximately MMT
 			 0:00	-	GMT
 
 ###############################################################################
@@ -596,7 +597,7 @@ Rule Mauritius	2008	only	-	Oct	lastSun	2:00	1:00	S
 Rule Mauritius	2009	only	-	Mar	lastSun	2:00	0	-
 # Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
 Zone Indian/Mauritius	3:50:00 -	LMT	1907 # Port Louis
-			4:00 Mauritius	MU%sT	# Mauritius Time
+			4:00 Mauritius	+04/+05
 # Agalega Is, Rodriguez
 # no information; probably like Indian/Mauritius
 
@@ -915,14 +916,14 @@ Zone Africa/Casablanca	-0:30:20 -	LMT	1913 Oct 26
 # since most of it was then controlled by Morocco.
 
 Zone Africa/El_Aaiun	-0:52:48 -	LMT	1934 Jan # El Aaiún
-			-1:00	-	WAT	1976 Apr 14
+			-1:00	-	-01	1976 Apr 14
 			 0:00	Morocco	WE%sT
 
 # Mozambique
 #
 # Shanks gives 1903-03-01 for the transition to CAT.
 # Perhaps the 1911-05-26 Portuguese decree
-# http://dre.pt/pdf1sdip/1911/05/12500/23132313.pdf
+# https://dre.pt/pdf1sdip/1911/05/12500/23132313.pdf
 # merely made it official?
 #
 # Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
@@ -949,16 +950,19 @@ Link Africa/Maputo Africa/Lusaka	# Zambia
 # the country are close to 40 minutes earlier in sunrise than the rest
 # of the country.
 #
-# From Paul Eggert (2007-03-31):
-# Apparently the Caprivi Strip informally observes Botswana time, but
-# we have no details.  In the meantime people there can use Africa/Gaborone.
+# From Paul Eggert (2017-02-22):
+# Although the Zambezi Region (formerly known as Caprivi) informally
+# observes Botswana time, we have no details about historical practice.
+# In the meantime people there can use Africa/Gaborone.
+# See: Immanuel S. The Namibian. 2017-02-23.
+# http://www.namibian.com.na/51480/read/Time-change-divides-lawmakers
 
 # RULE	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
 Rule	Namibia	1994	max	-	Sep	Sun>=1	2:00	1:00	S
 Rule	Namibia	1995	max	-	Apr	Sun>=1	2:00	0	-
 # Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
 Zone	Africa/Windhoek	1:08:24 -	LMT	1892 Feb 8
-			1:30	-	SWAT	1903 Mar    # SW Africa Time
+			1:30	-	+0130	1903 Mar
 			2:00	-	SAST	1942 Sep 20  2:00
 			2:00	1:00	SAST	1943 Mar 21  2:00
 			2:00	-	SAST	1990 Mar 21 # independence
@@ -985,7 +989,7 @@ Link Africa/Lagos Africa/Porto-Novo  # Benin
 # Réunion
 # Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
 Zone	Indian/Reunion	3:41:52 -	LMT	1911 Jun # Saint-Denis
-			4:00	-	RET	# Réunion Time
+			4:00	-	+04
 #
 # Crozet Islands also observes Réunion time; see the 'antarctica' file.
 #
@@ -1020,7 +1024,7 @@ Zone	Indian/Reunion	3:41:52 -	LMT	1911 Jun # Saint-Denis
 # Seychelles
 # Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
 Zone	Indian/Mahe	3:41:48 -	LMT	1906 Jun # Victoria
-			4:00	-	SCT	# Seychelles Time
+			4:00	-	+04
 # From Paul Eggert (2001-05-30):
 # Aldabra, Farquhar, and Desroches, originally dependencies of the
 # Seychelles, were transferred to the British Indian Ocean Territory

src/timezone/data/antarctica

@@ -110,7 +110,8 @@ Zone Antarctica/Mawson	0	-	-00	1954 Feb 13
 # O'Higgins, Antarctic Peninsula, -6319-05704, since 1948-02
 # Prat, -6230-05941
 # Villa Las Estrellas (a town), around the Frei base, since 1984-04-09
-# These locations have always used Santiago time; use TZ='America/Santiago'.
+# These locations employ Region of Magallanes time; use
+# TZ='America/Punta_Arenas'.
 
 # China - year-round bases
 # Great Wall, King George Island, -6213-05858, since 1985-02-20

src/timezone/data/backward

@@ -96,6 +96,7 @@ Link	Pacific/Auckland	NZ
 Link	Pacific/Chatham		NZ-CHAT
 Link	America/Denver		Navajo
 Link	Asia/Shanghai		PRC
+Link	Pacific/Honolulu	Pacific/Johnston
 Link	Pacific/Pohnpei		Pacific/Ponape
 Link	Pacific/Pago_Pago	Pacific/Samoa
 Link	Pacific/Chuuk		Pacific/Truk

src/timezone/data/backzone

@@ -65,7 +65,7 @@ Link Africa/Asmara Africa/Asmera
 # Mali (southern)
 Zone	Africa/Bamako	-0:32:00 -	LMT	1912
 			 0:00	-	GMT	1934 Feb 26
-			-1:00	-	WAT	1960 Jun 20
+			-1:00	-	-01	1960 Jun 20
 			 0:00	-	GMT
 
 # Central African Republic
@@ -75,7 +75,7 @@ Zone	Africa/Bangui	1:14:20	-	LMT	1912
 # Gambia
 Zone	Africa/Banjul	-1:06:36 -	LMT	1912
 			-1:06:36 -	BMT	1935 # Banjul Mean Time
-			-1:00	-	WAT	1964
+			-1:00	-	-01	1964
 			 0:00	-	GMT
 
 # Malawi
@@ -93,18 +93,18 @@ Zone Africa/Bujumbura	1:57:28	-	LMT	1890
 # Guinea
 Zone	Africa/Conakry	-0:54:52 -	LMT	1912
 			 0:00	-	GMT	1934 Feb 26
-			-1:00	-	WAT	1960
+			-1:00	-	-01	1960
 			 0:00	-	GMT
 
 # Senegal
 Zone	Africa/Dakar	-1:09:44 -	LMT	1912
-			-1:00	-	WAT	1941 Jun
+			-1:00	-	-01	1941 Jun
 			 0:00	-	GMT
 
 # Tanzania
 Zone Africa/Dar_es_Salaam 2:37:08 -	LMT	1931
 			3:00	-	EAT	1948
-			2:45	-	BEAUT	1961
+			2:45	-	+0245	1961
 			3:00	-	EAT
 
 # Djibouti
@@ -122,14 +122,14 @@ Zone	Africa/Douala	0:38:48	-	LMT	1912
 # The International Hydrographic Bulletin, 1932-33, p 63 says that
 # Sierra Leone would advance its clocks by 20 minutes on 1933-10-01.
 # Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
-Rule	SL	1935	1942	-	Jun	 1	0:00	0:40	SLST
-Rule	SL	1935	1942	-	Oct	 1	0:00	0	WAT
-Rule	SL	1957	1962	-	Jun	 1	0:00	1:00	SLST
+Rule	SL	1935	1942	-	Jun	 1	0:00	0:40	-0020
+Rule	SL	1935	1942	-	Oct	 1	0:00	0	-01
+Rule	SL	1957	1962	-	Jun	 1	0:00	1:00	+01
 Rule	SL	1957	1962	-	Sep	 1	0:00	0	GMT
 Zone	Africa/Freetown	-0:53:00 -	LMT	1882
 			-0:53:00 -	FMT	1913 Jun # Freetown Mean Time
 			-1:00	SL	%s	1957
-			 0:00	SL	%s
+			 0:00	SL	GMT/+01
 
 # Botswana
 # From Paul Eggert (2013-02-21):
@@ -153,8 +153,8 @@ Zone	Africa/Juba	2:06:24 -	LMT	1931
 # Uganda
 Zone	Africa/Kampala	2:09:40 -	LMT	1928 Jul
 			3:00	-	EAT	1930
-			2:30	-	BEAT	1948
-			2:45	-	BEAUT	1957
+			2:30	-	+0230	1948
+			2:45	-	+0245	1957
 			3:00	-	EAT
 
 # Rwanda
@@ -177,11 +177,11 @@ Zone	Africa/Lome	0:04:52 -	LMT	1893
 #
 # Shanks gives 1911-05-26 for the transition to WAT,
 # evidently confusing the date of the Portuguese decree
-# http://dre.pt/pdf1sdip/1911/05/12500/23132313.pdf
+# https://dre.pt/pdf1sdip/1911/05/12500/23132313.pdf
 # with the date that it took effect, namely 1912-01-01.
 #
 Zone	Africa/Luanda	0:52:56	-	LMT	1892
-			0:52:04	-	AOT	1912 Jan  1 # Angola Time
+			0:52:04	-	+005204	1912 Jan  1
 			1:00	-	WAT
 
 # Democratic Republic of the Congo (east)
@@ -216,19 +216,19 @@ Zone	Africa/Mbabane	2:04:24 -	LMT	1903 Mar
 # Somalia
 Zone Africa/Mogadishu	3:01:28 -	LMT	1893 Nov
 			3:00	-	EAT	1931
-			2:30	-	BEAT	1957
+			2:30	-	+0230	1957
 			3:00	-	EAT
 
 # Niger
 Zone	Africa/Niamey	 0:08:28 -	LMT	1912
-			-1:00	-	WAT	1934 Feb 26
+			-1:00	-	-01	1934 Feb 26
 			 0:00	-	GMT	1960
 			 1:00	-	WAT
 
 # Mauritania
 Zone Africa/Nouakchott	-1:03:48 -	LMT	1912
 			 0:00	-	GMT	1934 Feb 26
-			-1:00	-	WAT	1960 Nov 28
+			-1:00	-	-01	1960 Nov 28
 			 0:00	-	GMT
 
 # Burkina Faso
@@ -264,19 +264,19 @@ Zone	America/Antigua	-4:07:12 -	LMT	1912 Mar 2
 # The name "Comodoro Rivadavia" exceeds the 14-byte POSIX limit.
 Zone America/Argentina/ComodRivadavia -4:30:00 - LMT	1894 Oct 31
 			-4:16:48 -	CMT	1920 May
-			-4:00	-	ART	1930 Dec
-			-4:00	Arg	AR%sT	1969 Oct  5
-			-3:00	Arg	AR%sT	1991 Mar  3
-			-4:00	-	WART	1991 Oct 20
-			-3:00	Arg	AR%sT	1999 Oct  3
-			-4:00	Arg	AR%sT	2000 Mar  3
-			-3:00	-	ART	2004 Jun  1
-			-4:00	-	WART	2004 Jun 20
-			-3:00	-	ART
+			-4:00	-	-04	1930 Dec
+			-4:00	Arg	-04/-03	1969 Oct  5
+			-3:00	Arg	-03/-02	1991 Mar  3
+			-4:00	-	-04	1991 Oct 20
+			-3:00	Arg	-03/-02	1999 Oct  3
+			-4:00	Arg	-04/-03	2000 Mar  3
+			-3:00	-	-03	2004 Jun  1
+			-4:00	-	-04	2004 Jun 20
+			-3:00	-	-03
 
 # Aruba
 Zone	America/Aruba	-4:40:24 -	LMT	1912 Feb 12 # Oranjestad
-			-4:30	-	ANT	1965 # Netherlands Antilles Time
+			-4:30	-	-0430	1965
 			-4:00	-	AST
 
 # Cayman Is
@@ -365,12 +365,12 @@ Zone America/Montserrat	-4:08:52 -	LMT	1911 Jul  1  0:01 # Cork Hill
 # Formosa (FM), La Pampa (LP), Chubut (CH)
 Zone America/Rosario	-4:02:40 -	LMT	1894 Nov
 			-4:16:44 -	CMT	1920 May
-			-4:00	-	ART	1930 Dec
-			-4:00	Arg	AR%sT	1969 Oct  5
-			-3:00	Arg	AR%sT	1991 Jul
-			-3:00	-	ART	1999 Oct  3  0:00
-			-4:00	Arg	AR%sT	2000 Mar  3  0:00
-			-3:00	-	ART
+			-4:00	-	-04	1930 Dec
+			-4:00	Arg	-04/-03	1969 Oct  5
+			-3:00	Arg	-03/-02	1991 Jul
+			-3:00	-	-03	1999 Oct  3  0:00
+			-4:00	Arg	-04/-03	2000 Mar  3  0:00
+			-3:00	-	-03
 
 # St Kitts-Nevis
 Zone America/St_Kitts	-4:10:52 -	LMT	1912 Mar  2 # Basseterre
@@ -403,12 +403,12 @@ Link Antarctica/McMurdo Antarctica/South_Pole
 # Milne says 2:59:54 was the meridian of the saluting battery at Aden,
 # and that Yemen was at 1:55:56, the meridian of the Hagia Sophia.
 Zone	Asia/Aden	2:59:54	-	LMT	1950
-			3:00	-	AST
+			3:00	-	+03
 
 # Bahrain
 Zone	Asia/Bahrain	3:22:20 -	LMT	1920     # Manamah
-			4:00	-	GST	1972 Jun
-			3:00	-	AST
+			4:00	-	+04	1972 Jun
+			3:00	-	+03
 
 # India
 #
@@ -431,7 +431,7 @@ Zone	Asia/Bahrain	3:22:20 -	LMT	1920     # Manamah
 # counties Deqing, Enping, Kaiping, Luoding, Taishan, Xinxing,
 # Yangchun, Yangjiang, Yu'nan, and Yunfu.
 Zone	Asia/Chongqing	7:06:20	-	LMT	1928     # or Chungking
-			7:00	-	LONT	1980 May # Long-shu Time
+			7:00	-	+07	1980 May
 			8:00	PRC	C%sT
 Link Asia/Chongqing Asia/Chungking
 
@@ -442,43 +442,43 @@ Link Asia/Chongqing Asia/Chungking
 # October 1954, with exact date and time unspecified.
 Zone	Asia/Hanoi	7:03:24 -	LMT	1906 Jul  1
 			7:06:30	-	PLMT	1911 May  1
-			7:00	-	ICT	1942 Dec 31 23:00
-			8:00	-	IDT	1945 Mar 14 23:00
-			9:00	-	JST	1945 Sep  2
-			7:00	-	ICT	1947 Apr  1
-			8:00	-	IDT	1954 Oct
-			7:00	-	ICT
+			7:00	-	+07	1942 Dec 31 23:00
+			8:00	-	+08	1945 Mar 14 23:00
+			9:00	-	+09	1945 Sep  2
+			7:00	-	+07	1947 Apr  1
+			8:00	-	+08	1954 Oct
+			7:00	-	+07
 
 # China
 # Changbai Time ("Long-white Time", Long-white = Heilongjiang area)
 # Heilongjiang (except Mohe county), Jilin
 Zone	Asia/Harbin	8:26:44	-	LMT	1928     # or Haerbin
-			8:30	-	CHAT	1932 Mar # Changbai Time
+			8:30	-	+0830	1932 Mar
 			8:00	-	CST	1940
-			9:00	-	CHAT	1966 May
-			8:30	-	CHAT	1980 May
+			9:00	-	+09	1966 May
+			8:30	-	+0830	1980 May
 			8:00	PRC	C%sT
 
 # far west China
 Zone	Asia/Kashgar	5:03:56	-	LMT	1928     # or Kashi or Kaxgar
-			5:30	-	KAST	1940     # Kashgar Time
-			5:00	-	KAST	1980 May
+			5:30	-	+0530	1940
+			5:00	-	+05	1980 May
 			8:00	PRC	C%sT
 
 # Kuwait
 Zone	Asia/Kuwait	3:11:56 -	LMT	1950
-			3:00	-	AST
+			3:00	-	+03
 
 
 # Oman
 # Milne says 3:54:24 was the meridian of the Muscat Tidal Observatory.
 Zone	Asia/Muscat	3:54:24 -	LMT	1920
-			4:00	-	GST
+			4:00	-	+04
 
 # India
 # From Paul Eggert (2014-08-11), after a heads-up from Stephen Colebourne:
 # According to a Portuguese decree (1911-05-26)
-# http://dre.pt/pdf1sdip/1911/05/12500/23132313.pdf
+# https://dre.pt/pdf1sdip/1911/05/12500/23132313.pdf
 # Portuguese India switched to UT +05 on 1912-01-01.
 #Zone	Asia/Panaji	[not enough info to complete]
 
@@ -491,12 +491,12 @@ Zone	Asia/Muscat	3:54:24 -	LMT	1920
 # transitions there.
 Zone	Asia/Phnom_Penh	6:59:40 -	LMT	1906 Jul  1
 			7:06:30	-	PLMT	1911 May  1
-			7:00	-	ICT	1942 Dec 31 23:00
-			8:00	-	IDT	1945 Mar 14 23:00
-			9:00	-	JST	1945 Sep  2
-			7:00	-	ICT	1947 Apr  1
-			8:00	-	IDT	1953 Nov  9
-			7:00	-	ICT
+			7:00	-	+07	1942 Dec 31 23:00
+			8:00	-	+08	1945 Mar 14 23:00
+			9:00	-	+09	1945 Sep  2
+			7:00	-	+07	1947 Apr  1
+			8:00	-	+08	1953 Nov  9
+			7:00	-	+07
 
 # Israel
 Zone	Asia/Tel_Aviv	2:19:04 -	LMT	1880
@@ -511,16 +511,16 @@ Zone	Asia/Tel_Aviv	2:19:04 -	LMT	1880
 # this is probably wrong but it's better than guessing no transition.
 Zone	Asia/Vientiane	6:50:24 -	LMT	1906 Jul  1
 			7:06:30	-	PLMT	1911 May  1
-			7:00	-	ICT	1942 Dec 31 23:00
-			8:00	-	IDT	1945 Mar 14 23:00
-			9:00	-	JST	1945 Sep  2
-			7:00	-	ICT	1947 Apr  1
-			8:00	-	IDT	1955 Apr 15
-			7:00	-	ICT
+			7:00	-	+07	1942 Dec 31 23:00
+			8:00	-	+08	1945 Mar 14 23:00
+			9:00	-	+09	1945 Sep  2
+			7:00	-	+07	1947 Apr  1
+			8:00	-	+08	1955 Apr 15
+			7:00	-	+07
 
 # Jan Mayen
 # From Whitman:
-Zone Atlantic/Jan_Mayen	-1:00	-	EGT
+Zone Atlantic/Jan_Mayen	-1:00	-	-01
 
 # St Helena
 Zone Atlantic/St_Helena	-0:22:48 -	LMT	1890 # Jamestown
@@ -663,15 +663,13 @@ Zone Pacific/Johnston	-10:00	-	HST
 #  "   3:00P Ar. MIDWAY ISLAND . . . . . . . . . M.L.T. Lv. 6:00A  "
 #
 Zone Pacific/Midway	-11:49:28 -	LMT	1901
-			-11:00	-	NST	1956 Jun  3
-			-11:00	1:00	NDT	1956 Sep  2
-			-11:00	-	NST	1967 Apr    # N=Nome
-			-11:00	-	BST	1983 Nov 30 # B=Bering
-			-11:00	-	SST	            # S=Samoa
+			-11:00	-	-11	1956 Jun  3
+			-11:00	1:00	-10	1956 Sep  2
+			-11:00	-	-11
 
 # N Mariana Is
 Zone Pacific/Saipan	-14:17:00 -	LMT	1844 Dec 31
 			 9:43:00 -	LMT	1901
-			 9:00	-	MPT	1969 Oct    # N Mariana Is Time
-			10:00	-	MPT	2000 Dec 23
+			 9:00	-	+09	1969 Oct
+			10:00	-	+10	2000 Dec 23
 			10:00	-	ChST	# Chamorro Standard Time

src/timezone/data/northamerica

@@ -178,22 +178,6 @@ Zone	CST6CDT		 -6:00	US	C%sT
 Zone	MST7MDT		 -7:00	US	M%sT
 Zone	PST8PDT		 -8:00	US	P%sT
 
-# From Bob Devine (1988-01-28):
-# ...Alaska (and Hawaii) had the timezone names changed in 1967.
-#    old			 new
-#    Pacific Standard Time(PST)  -same-
-#    Yukon Standard Time(YST)    -same-
-#    Central Alaska S.T. (CAT)   Alaska-Hawaii St[an]dard Time (AHST)
-#    Nome Standard Time (NT)     Bering Standard Time (BST)
-#
-# ...Alaska's timezone lines were redrawn in 1983 to give only 2 tz.
-#    The YST zone now covers nearly all of the state, AHST just part
-#    of the Aleutian islands.   No DST.
-
-# From Paul Eggert (1995-12-19):
-# The tables below use 'NST', not 'NT', for Nome Standard Time.
-# I invented 'CAWT' for Central Alaska War Time.
-
 # From U. S. Naval Observatory (1989-01-19):
 # USA  EASTERN       5 H  BEHIND UTC    NEW YORK, WASHINGTON
 # USA  EASTERN       4 H  BEHIND UTC    APR 3 - OCT 30
@@ -250,6 +234,21 @@ Zone	PST8PDT		 -8:00	US	P%sT
 #	Samoa standard time
 # The law doesn't give abbreviations.
 #
+# From Paul Eggert (2016-12-19):
+# Here are URLs for the 1918 and 1966 legislation:
+# http://uscode.house.gov/statviewer.htm?volume=40&page=451
+# http://uscode.house.gov/statviewer.htm?volume=80&page=108
+# Although the 1918 names were officially "United States Standard
+# Eastern Time" and similarly for "Central", "Mountain", "Pacific",
+# and "Alaska", in practice "Standard" was placed just before "Time",
+# as codified in 1966.  In practice, Alaska time was abbreviated "AST"
+# before 1968.  Summarizing the 1967 name changes:
+#	1918 names			1967 names
+#  -08	Standard Pacific Time (PST)	Pacific standard time (PST)
+#  -09	(unofficial) Yukon (YST)	Yukon standard time (YST)
+#  -10	Standard Alaska Time (AST)	Alaska-Hawaii standard time (AHST)
+#  -11	(unofficial) Nome (NST)		Bering standard time (BST)
+#
 # From Paul Eggert (2000-01-08), following a heads-up from Rives McDow:
 # Public law 106-564 (2000-12-23) introduced ... "Chamorro Standard Time"
 # for time in Guam and the Northern Marianas.  See the file "australasia".
@@ -305,6 +304,15 @@ Zone	PST8PDT		 -8:00	US	P%sT
 # Roberts, city administrator in Phenix City. as saying "We are in the Central
 # time zone, but we do go by the Eastern time zone because so many people work
 # in Columbus."
+#
+# From Paul Eggert (2017-02-22):
+# Four cities are involved.  The two not mentioned above are Smiths Station
+# and Valley.  Barbara Brooks, Valley's assistant treasurer, heard it started
+# because West Point Pepperell textile mills were in Alabama while the
+# corporate office was in Georgia, and residents voted to keep Eastern
+# time even after the mills closed.  See: Kazek K. Did you know which
+# Alabama towns are in a different time zone?  al.com 2017-02-06.
+# http://www.al.com/living/index.ssf/2017/02/do_you_know_which_alabama_town.html
 
 # From Paul Eggert (2014-09-06):
 # Monthly Notices of the Royal Astronomical Society 44, 4 (1884-02-08), 208
@@ -482,7 +490,7 @@ Zone America/Los_Angeles -7:52:58 -	LMT	1883 Nov 18 12:07:02
 			-8:00	US	P%sT
 
 # Alaska
-# AK%sT is the modern abbreviation for -9:00 per USNO.
+# AK%sT is the modern abbreviation for -09 per USNO.
 #
 # From Paul Eggert (2001-05-30):
 # Howse writes that Alaska switched from the Julian to the Gregorian calendar,
@@ -588,10 +596,8 @@ Zone America/Yakutat	 14:41:05 -	LMT	1867 Oct 18
 			 -9:00	US	AK%sT
 Zone America/Anchorage	 14:00:24 -	LMT	1867 Oct 18
 			 -9:59:36 -	LMT	1900 Aug 20 12:00
-			-10:00	-	CAT	1942
-			-10:00	US	CAT/CAWT 1945 Aug 14 23:00u
-			-10:00	US	CAT/CAPT 1946 # Peace
-			-10:00	-	CAT	1967 Apr
+			-10:00	-	AST	1942
+			-10:00	US	A%sT	1967 Apr
 			-10:00	-	AHST	1969
 			-10:00	US	AH%sT	1983 Oct 30  2:00
 			 -9:00	US	Y%sT	1983 Nov 30
@@ -680,7 +686,6 @@ Zone Pacific/Honolulu	-10:31:26 -	LMT	1896 Jan 13 12:00
 			-10:30	1:00	HDT	1945 Sep 30  2:00
 			-10:30	-	HST	1947 Jun  8  2:00
 			-10:00	-	HST
-Link Pacific/Honolulu Pacific/Johnston
 
 # Now we turn to US areas that have diverged from the consensus since 1970.
 
@@ -1068,15 +1073,15 @@ Zone America/Menominee	-5:50:27 -	LMT	1885 Sep 18 12:00
 ################################################################################
 
 
-# From Paul Eggert (2014-10-31):
+# From Paul Eggert (2017-02-10):
 #
 # Unless otherwise specified, the source for data through 1990 is:
 # Thomas G. Shanks and Rique Pottenger, The International Atlas (6th edition),
 # San Diego: ACS Publications, Inc. (2003).
 # Unfortunately this book contains many errors and cites no sources.
 #
-# Gwillim Law writes that a good source
-# for recent time zone data is the International Air Transport
+# Many years ago Gwillim Law wrote that a good source
+# for time zone data was the International Air Transport
 # Association's Standard Schedules Information Manual (IATA SSIM),
 # published semiannually.  Law sent in several helpful summaries
 # of the IATA's data after 1990.  Except where otherwise noted,
@@ -2734,15 +2739,15 @@ Zone America/Barbados	-3:58:29 -	LMT	1924 # Bridgetown
 # Belize
 # Whitman entirely disagrees with Shanks; go with Shanks & Pottenger.
 # Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
-Rule	Belize	1918	1942	-	Oct	Sun>=2	0:00	0:30	HD
-Rule	Belize	1919	1943	-	Feb	Sun>=9	0:00	0	S
-Rule	Belize	1973	only	-	Dec	 5	0:00	1:00	D
-Rule	Belize	1974	only	-	Feb	 9	0:00	0	S
-Rule	Belize	1982	only	-	Dec	18	0:00	1:00	D
-Rule	Belize	1983	only	-	Feb	12	0:00	0	S
+Rule	Belize	1918	1942	-	Oct	Sun>=2	0:00	0:30	-0530
+Rule	Belize	1919	1943	-	Feb	Sun>=9	0:00	0	CST
+Rule	Belize	1973	only	-	Dec	 5	0:00	1:00	CDT
+Rule	Belize	1974	only	-	Feb	 9	0:00	0	CST
+Rule	Belize	1982	only	-	Dec	18	0:00	1:00	CDT
+Rule	Belize	1983	only	-	Feb	12	0:00	0	CST
 # Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
 Zone	America/Belize	-5:52:48 -	LMT	1912 Apr
-			-6:00	Belize	C%sT
+			-6:00	Belize	%s
 
 # Bermuda
 
@@ -3014,16 +3019,16 @@ Zone	America/Havana	-5:29:28 -	LMT	1890
 
 
 # Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
-Rule	DR	1966	only	-	Oct	30	0:00	1:00	D
-Rule	DR	1967	only	-	Feb	28	0:00	0	S
-Rule	DR	1969	1973	-	Oct	lastSun	0:00	0:30	HD
-Rule	DR	1970	only	-	Feb	21	0:00	0	S
-Rule	DR	1971	only	-	Jan	20	0:00	0	S
-Rule	DR	1972	1974	-	Jan	21	0:00	0	S
+Rule	DR	1966	only	-	Oct	30	0:00	1:00	EDT
+Rule	DR	1967	only	-	Feb	28	0:00	0	EST
+Rule	DR	1969	1973	-	Oct	lastSun	0:00	0:30	-0430
+Rule	DR	1970	only	-	Feb	21	0:00	0	EST
+Rule	DR	1971	only	-	Jan	20	0:00	0	EST
+Rule	DR	1972	1974	-	Jan	21	0:00	0	EST
 # Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
 Zone America/Santo_Domingo -4:39:36 -	LMT	1890
 			-4:40	-	SDMT	1933 Apr  1 12:00 # S. Dom. MT
-			-5:00	DR	E%sT	1974 Oct 27
+			-5:00	DR	%s	1974 Oct 27
 			-4:00	-	AST	2000 Oct 29  2:00
 			-5:00	US	E%sT	2000 Dec  3  1:00
 			-4:00	-	AST
@@ -3134,6 +3139,12 @@ Zone America/Guatemala	-6:02:04 -	LMT	1918 Oct 5
 # http://www.vantbefinfo.com/changement-dheure-pas-pour-haiti/
 # http://news.anmwe.com/haiti-lheure-nationale-ne-sera-ni-avancee-ni-reculee-cette-annee/
 
+# From Steffen Thorsen (2017-03-12):
+# We have received 4 mails from different people telling that Haiti
+# has started DST again today, and this source seems to confirm that,
+# I have not been able to find a more authoritative source:
+# https://www.haitilibre.com/en/news-20319-haiti-notices-time-change-in-haiti.html
+
 # Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
 Rule	Haiti	1983	only	-	May	8	0:00	1:00	D
 Rule	Haiti	1984	1987	-	Apr	lastSun	0:00	1:00	D
@@ -3146,6 +3157,8 @@ Rule	Haiti	2005	2006	-	Apr	Sun>=1	0:00	1:00	D
 Rule	Haiti	2005	2006	-	Oct	lastSun	0:00	0	S
 Rule	Haiti	2012	2015	-	Mar	Sun>=8	2:00	1:00	D
 Rule	Haiti	2012	2015	-	Nov	Sun>=1	2:00	0	S
+Rule	Haiti	2017	max	-	Mar	Sun>=8	2:00	1:00	D
+Rule	Haiti	2017	max	-	Nov	Sun>=1	2:00	0	S
 # Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
 Zone America/Port-au-Prince -4:49:20 -	LMT	1890
 			-4:49	-	PPMT	1917 Jan 24 12:00 # P-a-P MT
@@ -3313,8 +3326,8 @@ Zone America/Puerto_Rico -4:24:25 -	LMT	1899 Mar 28 12:00 # San Juan
 # Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
 Zone America/Miquelon	-3:44:40 -	LMT	1911 May 15 # St Pierre
 			-4:00	-	AST	1980 May
-			-3:00	-	PMST	1987 # Pierre & Miquelon Time
-			-3:00	Canada	PM%sT
+			-3:00	-	-03	1987
+			-3:00	Canada	-03/-02
 
 # St Vincent and the Grenadines
 # See America/Port_of_Spain.

src/timezone/known_abbrevs.txt

 +00	0
++00	0	D
 +01	3600
 +02	7200
 +02	7200	D
 +03	10800
++0330	12600
 +04	14400
++0430	16200
++0430	16200	D
 +05	18000
 +0530	19800
++0545	20700
 +06	21600
++0630	23400
 +07	25200
 +08	28800
++0845	31500
 +09	32400
 +10	36000
++1030	37800
 +11	39600
++11	39600	D
 +12	43200
++1245	45900
 +13	46800
++13	46800	D
++1345	49500	D
 +14	50400
 +14	50400	D
 -00	0
 -01	-3600
 -02	-7200
+-02	-7200	D
 -03	-10800
+-03	-10800	D
 -04	-14400
 -05	-18000
+-05	-18000	D
 -06	-21600
 -07	-25200
 -08	-28800
 -09	-32400
+-0930	-34200
 -10	-36000
 -11	-39600
 -12	-43200
 ACDT	37800	D
 ACST	34200
-ACT	-18000
-ACWST	31500
 ADT	-10800	D
 AEDT	39600	D
 AEST	36000
-AFT	16200
 AKDT	-28800	D
 AKST	-32400
-AMST	-10800	D
-AMT	-14400
-ART	-10800
 AST	-14400
-AST	10800
 AWST	28800
-AZOST	0	D
-AZOT	-3600
-BDT	21600
-BNT	28800
-BOT	-14400
-BRST	-7200	D
-BRT	-10800
 BST	3600	D
-BST	39600
-BTT	21600
 CAT	7200
-CCT	23400
 CDT	-14400	D
 CDT	-18000	D
 CEST	7200	D
 CET	3600
-CHADT	49500	D
-CHAST	45900
-CHOST	32400	D
-CHOT	28800
-CHUT	36000
-CKT	-36000
-CLST	-10800	D
-CLT	-14400
-COT	-18000
 CST	-18000
 CST	-21600
 CST	28800
-CVT	-3600
-CXT	25200
 ChST	36000
-EASST	-18000	D
-EAST	-21600
 EAT	10800
-ECT	-18000
 EDT	-14400	D
 EEST	10800	D
 EET	7200
-EGST	0	D
-EGT	-3600
 EST	-18000
-FJST	46800	D
-FJT	43200
-FKST	-10800
-FNT	-7200
-GALT	-21600
-GAMT	-32400
-GFT	-10800
-GILT	43200
 GMT	0
-GST	-7200
-GST	14400
-GYT	-14400
 HDT	-32400	D
 HKT	28800
-HOVST	28800	D
-HOVT	25200
 HST	-36000
-ICT	25200
 IDT	10800	D
-IOT	21600
-IRDT	16200	D
-IRST	12600
 IST	19800
 IST	3600	D
 IST	7200
 JST	32400
-KOST	39600
 KST	30600
 KST	32400
-LHDT	39600	D
-LHST	37800
-LINT	50400
-MART	-34200
 MDT	-21600	D
 MEST	7200	D
 MET	3600
-MHT	43200
-MIST	39600
-MMT	23400
 MSK	10800
 MST	-25200
-MUT	14400
-MVT	18000
-MYT	28800
-NCT	39600
 NDT	-9000	D
-NFT	39600
-NPT	20700
-NRT	43200
 NST	-12600
-NUT	-39600
 NZDT	46800	D
 NZST	43200
 PDT	-25200	D
-PET	-18000
-PGT	36000
-PHOT	46800
-PHT	28800
 PKT	18000
-PMDT	-7200	D
-PMST	-10800
-PONT	39600
 PST	-28800
-PWT	32400
-PYST	-10800	D
-PYT	-14400
-RET	14400
 SAST	7200
-SBT	39600
-SCT	14400
-SGT	28800
-SRT	-10800
 SST	-39600
-TAHT	-36000
-TKT	46800
-TLT	32400
-TVT	43200
 UCT	0
-ULAST	32400	D
-ULAT	28800
 UTC	0
-UYT	-10800
-VET	-14400
-VUT	39600
-WAKT	43200
 WAST	7200	D
 WAT	3600
 WEST	3600	D
 WET	0
-WFT	43200
-WGST	-7200	D
-WGT	-10800
 WIB	25200
 WIT	32400
 WITA	28800
-WSDT	50400	D
-WSST	46800
-XJT	21600

src/timezone/tznames/America.txt

@@ -9,9 +9,7 @@
 
 # Acre time is sometimes called Acre Standard Time (AST) which leads to a
 # conflict with AST (see below at AST)
-ACT    -18000    # Acre Time
-                 #     (America/Eirunepe)
-                 #     (America/Rio_Branco)
+ACT    -18000    # Acre Time (obsolete)
 # CONFLICT! ACST is not unique
 # Other timezones:
 #  - ACST: Australian Central Standard Time
@@ -35,30 +33,13 @@ AKST   -32400    # Alaska Standard Time
 # CONFLICT! AMST is not unique
 # Other timezones:
 #  - AMST: Armenia Summer Time (Asia)
-AMST   -10800 D  # Amazon Summer Time
-                 #     (America/Campo_Grande)
-                 #     (America/Cuiaba)
+AMST   -10800 D  # Amazon Summer Time (obsolete)
 # CONFLICT! AMT is not unique
 # Other timezones:
 #  - AMT: Armenia Time (Asia)
-AMT    -14400    # Amazon Time
-                 #     (America/Boa_Vista)
-                 #     (America/Campo_Grande)
-                 #     (America/Cuiaba)
-                 #     (America/Manaus)
-                 #     (America/Porto_Velho)
-ART    America/Argentina/Buenos_Aires  # Argentina Time
-                 #     (America/Argentina/Buenos_Aires)
-                 #     (America/Argentina/Cordoba)
-                 #     (America/Argentina/Tucuman)
-                 #     (America/Argentina/La_Rioja)
-                 #     (America/Argentina/San_Juan)
-                 #     (America/Argentina/Jujuy)
-                 #     (America/Argentina/Catamarca)
-                 #     (America/Argentina/Mendoza)
-                 #     (America/Argentina/Rio_Gallegos)
-                 #     (America/Argentina/Ushuaia)
-ARST    America/Argentina/Buenos_Aires  # Argentina Summer Time
+AMT    -14400    # Amazon Time (obsolete)
+ART    America/Argentina/Buenos_Aires  # Argentina Time (obsolete)
+ARST    America/Argentina/Buenos_Aires  # Argentina Summer Time (obsolete)
 # CONFLICT! AST is not unique
 # Other timezones:
 #  - AST: Arabic Standard Time (Asia)
@@ -90,19 +71,10 @@ AST    -14400    # Atlantic Standard Time
                  #     (America/Thule)
                  #     (America/Tortola)
                  #     (Atlantic/Bermuda)
-BOT    -14400    # Bolivia Time
-                 #     (America/La_Paz)
+BOT    -14400    # Bolivia Time (obsolete)
 BRA    -10800    # Brazil Time (not in IANA database)
-BRST    -7200 D  # Brasil Summer Time
-                 #     (America/Sao_Paulo)
-BRT    -10800    # Brasil Time
-                 #     (America/Araguaina)
-                 #     (America/Bahia)
-                 #     (America/Belem)
-                 #     (America/Fortaleza)
-                 #     (America/Maceio)
-                 #     (America/Recife)
-                 #     (America/Sao_Paulo)
+BRST    -7200 D  # Brasil Summer Time (obsolete)
+BRT    -10800    # Brasil Time (obsolete)
 # CONFLICT! CDT is not unique
 # Other timezones:
 #  - CDT: Central Daylight Time (America)
@@ -125,13 +97,9 @@ CDT    -18000 D  # Central Daylight Time
                  #     (America/Rainy_River)
                  #     (America/Rankin_Inlet)
                  #     (America/Winnipeg)
-CLST   -10800 D  # Chile Summer Time
-                 #     (America/Santiago)
-                 #     (Antarctica/Palmer)
-CLT    America/Santiago  # Chile Time
-                 #     (America/Santiago)
-                 #     (Antarctica/Palmer)
-COT    -18000    # Columbia Time (not in IANA database)
+CLST   -10800 D  # Chile Summer Time (obsolete)
+CLT    America/Santiago  # Chile Time (obsolete)
+COT    -18000    # Columbia Time (obsolete)
 # CONFLICT! CST is not unique
 # Other timezones:
 #  - CST: Central Standard Time (Australia)
@@ -156,9 +124,7 @@ CST    -21600    # Central Standard Time (America)
                  #     (America/Regina)
                  #     (America/Swift_Current)
                  #     (America/Winnipeg)
-ECT    -18000    # Ecuador Time
-                 # Eastern Caribbean Time
-                 #     (America/Guayaquil)
+ECT    -18000    # Ecuador Time (obsolete)
 EDT    -14400 D  # Eastern Daylight Saving Time
                  #     (America/Detroit)
                  #     (America/Grand_Turk)
@@ -176,10 +142,8 @@ EDT    -14400 D  # Eastern Daylight Saving Time
                  #     (America/Pangnirtung)
                  #     (America/Thunder_Bay)
                  #     (America/Toronto)
-EGST        0 D  # East Greenland Summer Time
-                 #     (America/Scoresbysund)
-EGT     -3600    # East Greenland Time (Svalbard & Jan Mayen)
-                 #     (America/Scoresbysund)
+EGST        0 D  # East Greenland Summer Time (obsolete)
+EGT     -3600    # East Greenland Time (Svalbard & Jan Mayen) (obsolete)
 # CONFLICT! EST is not unique
 # Other timezones:
 #  - EST: Eastern Standard Time (Australia)
@@ -205,12 +169,9 @@ EST    -18000    # Eastern Standard Time (America)
                  #     (America/Pangnirtung)
                  #     (America/Thunder_Bay)
                  #     (America/Toronto)
-FNT     -7200    # Fernando de Noronha Time
-                 #     (America/Noronha)
-FNST    -3600 D  # Fernando de Noronha Summer Time (not in IANA database)
-                 #     (America/Noronha)
-GFT    -10800    # French Guiana Time
-                 #     (America/Cayenne)
+FNT     -7200    # Fernando de Noronha Time (obsolete)
+FNST    -3600 D  # Fernando de Noronha Summer Time (obsolete)
+GFT    -10800    # French Guiana Time (obsolete)
 GMT         0    # Greenwich Mean Time
                  #     (Africa/Abidjan)
                  #     (Africa/Bamako)
@@ -229,8 +190,7 @@ GMT         0    # Greenwich Mean Time
                  #     (Etc/GMT)
                  #     (Europe/Dublin)
                  #     (Europe/London)
-GYT    America/Guyana  # Guyana Time
-                 #     (America/Guyana)
+GYT    America/Guyana  # Guyana Time (obsolete)
 HADT   -32400 D  # Hawaii-Aleutian Daylight Time (obsolete abbreviation)
                  #     (America/Adak)
 HAST   -36000    # Hawaii-Aleutian Standard Time (obsolete abbreviation)
@@ -274,11 +234,9 @@ PDT    -25200 D  # Pacific Daylight Time
                  #     (America/Tijuana)
                  #     (America/Vancouver)
                  #     (America/Whitehorse)
-PET    -18000    # Peru Time (not in IANA database)
-PMDT    -7200 D  # Pierre & Miquelon Daylight Time
-                 #     (America/Miquelon)
-PMST   -10800    # Pierre & Miquelon Standard Time
-                 #     (America/Miquelon)
+PET    -18000    # Peru Time (obsolete)
+PMDT    -7200 D  # Pierre & Miquelon Daylight Time (obsolete)
+PMST   -10800    # Pierre & Miquelon Standard Time (obsolete)
 PST    -28800    # Pacific Standard Time
                  #     (America/Dawson)
                  #     (America/Los_Angeles)
@@ -286,19 +244,11 @@ PST    -28800    # Pacific Standard Time
                  #     (America/Vancouver)
                  #     (America/Whitehorse)
                  #     (Pacific/Pitcairn)
-PYST   -10800 D  # Paraguay Summer Time
-                 #     (America/Asuncion)
-PYT    America/Asuncion  # Paraguay Time
-                 #     (America/Asuncion)
-SRT    America/Paramaribo  # Suriname Time
-                 #     (America/Paramaribo)
+PYST   -10800 D  # Paraguay Summer Time (obsolete)
+PYT    America/Asuncion  # Paraguay Time (obsolete)
+SRT    America/Paramaribo  # Suriname Time (obsolete)
 UYST    -7200 D  # Uruguay Summer Time (obsolete)
-                 #     (America/Montevideo)
-UYT    -10800    # Uruguay Time
-                 #     (America/Montevideo)
-VET    America/Caracas  # Venezuela Time
-                 #     (America/Caracas)
-WGST    -7200 D  # Western Greenland Summer Time
-                 #     (America/Godthab)
-WGT    -10800    # West Greenland Time
-                 #     (America/Godthab)
+UYT    -10800    # Uruguay Time (obsolete)
+VET    America/Caracas  # Venezuela Time (obsolete)
+WGST    -7200 D  # Western Greenland Summer Time (obsolete)
+WGT    -10800    # West Greenland Time (obsolete)

src/timezone/tznames/Antarctica.txt

@@ -10,17 +10,12 @@
 AWST    28800    # Australian Western Standard Time
                  #     (Antarctica/Casey)
                  #     (Australia/Perth)
-CLST   -10800 D  # Chile Summer Time
-                 #     (America/Santiago)
-                 #     (Antarctica/Palmer)
-CLT    America/Santiago  # Chile Time
-                 #     (America/Santiago)
-                 #     (Antarctica/Palmer)
+CLST   -10800 D  # Chile Summer Time (obsolete)
+CLT    America/Santiago  # Chile Time (obsolete)
 DAVT    Antarctica/Davis  # Davis Time (Antarctica) (obsolete)
 DDUT    36000    # Dumont-d`Urville Time (Antarctica) (obsolete)
 MAWT    Antarctica/Mawson  # Mawson Time (Antarctica) (obsolete)
-MIST    39600    # Macquarie Island Time
-                 #     (Antarctica/Macquarie)
+MIST    39600    # Macquarie Island Time (obsolete)
 NZDT    46800 D  # New Zealand Daylight Time
                  #     (Antarctica/McMurdo)
                  #     (Pacific/Auckland)

src/timezone/tznames/Asia.txt

@@ -7,15 +7,13 @@
 # src/timezone/tznames/Asia.txt
 #
 
-AFT     16200    # Afghanistan Time
-                 #     (Asia/Kabul)
+AFT     16200    # Afghanistan Time (obsolete)
 ALMST   25200 D  # Alma-Ata Summer Time (obsolete)
 ALMT    21600    # Alma-Ata Time (obsolete)
 # CONFLICT! AMST is not unique
 # Other timezones:
 #  - AMST: Amazon Summer Time (America)
-AMST    Asia/Yerevan  # Armenia Summer Time
-                 #     (Asia/Yerevan)
+AMST    Asia/Yerevan  # Armenia Summer Time (obsolete)
 # CONFLICT! AMT is not unique
 # Other timezones:
 #  - AMT: Amazon Time (America)
@@ -32,27 +30,16 @@ AQTT    Asia/Aqtau  # Aqtau Time (obsolete)
 #  - AST: Antigua Standard Time (America) same offset as Atlantic Standard Time
 #  - AST: Antilles Standard Time (America) same offset as Atlantic Standard Time
 #  - AST: Al Manamah Standard Time (Asia) same offset as Arabia Standard Time
-AST     10800    # Arabia Standard Time
-                 #     (Asia/Aden)
-                 #     (Asia/Baghdad)
-                 #     (Asia/Bahrain)
-                 #     (Asia/Kuwait)
-                 #     (Asia/Qatar)
-                 #     (Asia/Riyadh)
+AST     10800    # Arabia Standard Time (obsolete)
 AZST    Asia/Baku  # Azerbaijan Summer Time (obsolete)
 AZT     Asia/Baku  # Azerbaijan Time (obsolete)
-BDT     21600    # Bangladesh Time
-                 #     (Asia/Dhaka)
-BNT     28800    # Brunei Darussalam Time
-                 #     (Asia/Brunei)
+BDT     21600    # Bangladesh Time (obsolete)
+BNT     28800    # Brunei Darussalam Time (obsolete)
 BORT    28800    # Borneo Time (Indonesia) (not in IANA database)
-BTT     21600    # Bhutan Time
-                 #     (Asia/Thimphu)
+BTT     21600    # Bhutan Time (obsolete)
 CCT     28800    # China Coastal Time (not in IANA database)
-CHOST   Asia/Choibalsan  # Choibalsan Summer Time
-                 #     (Asia/Choibalsan)
-CHOT    Asia/Choibalsan  # Choibalsan Time
-                 #     (Asia/Choibalsan)
+CHOST   Asia/Choibalsan  # Choibalsan Summer Time (obsolete)
+CHOT    Asia/Choibalsan  # Choibalsan Time (obsolete)
 CIT     28800    # Central Indonesia Time (obsolete, WITA is now preferred)
 # CONFLICT! CST is not unique
 # Other timezones:
@@ -116,27 +103,18 @@ GET     Asia/Tbilisi  # Georgia Time (obsolete)
 # CONFLICT! GST is not unique
 # Other timezones:
 # - GST: South Georgia Time (Atlantic)
-GST     14400    # Gulf Standard Time
-                 #     (Asia/Dubai)
-                 #     (Asia/Muscat)
-HKT     28800    # Hong Kong Time (not in IANA database)
-HOVST   28800 D  # Hovd Summer Time
-                 #     (Asia/Hovd)
-HOVT    Asia/Hovd  # Hovd Time
-                 #     (Asia/Hovd)
-ICT     25200    # Indochina Time
-                 #     (Asia/Bangkok)
-                 #     (Asia/Phnom_Penh)
-                 #     (Asia/Saigon)
-                 #     (Asia/Vientiane)
+GST     14400    # Gulf Standard Time (obsolete)
+HKT     28800    # Hong Kong Time
+                 #     (Asia/Hong_Kong)
+HOVST   28800 D  # Hovd Summer Time (obsolete)
+HOVT    Asia/Hovd  # Hovd Time (obsolete)
+ICT     25200    # Indochina Time (obsolete)
 IDT     10800 D  # Israel Daylight Time
                  #     (Asia/Jerusalem)
-IRDT    Asia/Tehran  # Iran Daylight Time
-                 #     (Asia/Tehran)
+IRDT    Asia/Tehran  # Iran Daylight Time (obsolete)
 IRKST   Asia/Irkutsk  # Irkutsk Summer Time (obsolete)
 IRKT    Asia/Irkutsk  # Irkutsk Time (obsolete)
-IRST    Asia/Tehran  # Iran Standard Time
-                 #     (Asia/Tehran)
+IRST    Asia/Tehran  # Iran Standard Time (obsolete)
 IRT     12600    # Iran Time (not in IANA database)
 # CONFLICT! IST is not unique
 # Other timezones:
@@ -165,22 +143,17 @@ KST     32400    # Korean Standard Time
 LKT     Asia/Colombo  # Lanka Time (obsolete)
 MAGST   Asia/Magadan  # Magadan Summer Time (obsolete)
 MAGT    Asia/Magadan  # Magadan Time (obsolete)
-MMT     23400    # Myanmar Time
-                 #     (Asia/Yangon)
-MYT     28800    # Malaysia Time
-                 #     (Asia/Kuala_Lumpur)
-                 #     (Asia/Kuching)
+MMT     23400    # Myanmar Time (obsolete)
+MYT     28800    # Malaysia Time (obsolete)
 NOVST   Asia/Novosibirsk  # Novosibirsk Summer Time (obsolete)
 NOVT    Asia/Novosibirsk  # Novosibirsk Time (obsolete)
-NPT     20700    # Nepal Time
-                 #     (Asia/Katmandu)
+NPT     20700    # Nepal Time (obsolete)
 OMSST   Asia/Omsk  # Omsk Summer Time (obsolete)
 OMST    Asia/Omsk  # Omsk Time (obsolete)
 ORAT    Asia/Oral  # Oral Time (obsolete)
 PETST   Asia/Kamchatka  # Petropavlovsk-Kamchatski Summer Time (obsolete)
 PETT    Asia/Kamchatka  # Petropavlovsk-Kamchatski Time (obsolete)
-PHT     28800    # Philippine Time
-                 #     (Asia/Manila)
+PHT     28800    # Philippine Time (obsolete)
 PKT     18000    # Pakistan Time
                  #     (Asia/Karachi)
 PKST    21600 D  # Pakistan Summer Time
@@ -188,20 +161,14 @@ PKST    21600 D  # Pakistan Summer Time
 QYZT    21600    # Kizilorda Time (obsolete)
 SAKST   Asia/Sakhalin  # Sakhalin Summer Time (obsolete)
 SAKT    Asia/Sakhalin  # Sakhalin Time (obsolete)
-SGT     Asia/Singapore  # Singapore Time
-                 #     (Asia/Singapore)
+SGT     Asia/Singapore  # Singapore Time (obsolete)
 SRET    39600    # Srednekolymsk Time (obsolete)
 TJT     18000    # Tajikistan Time (obsolete)
-TLT     32400    # East Timor Time
-                 #     (Asia/Dili)
+TLT     32400    # East Timor Time (obsolete)
 TMT     Asia/Ashgabat  # Turkmenistan Time (obsolete)
-ULAST   32400 D  # Ulan Bator Summer Time
-                 #     (Asia/Ulaanbaatar)
-ULAT    Asia/Ulaanbaatar  # Ulan Bator Time
-                 #     (Asia/Ulaanbaatar)
-UZST    21600 D  # Uzbekistan Summer Time
-                 #     (Asia/Samarkand)
-                 #     (Asia/Tashkent)
+ULAST   32400 D  # Ulan Bator Summer Time (obsolete)
+ULAT    Asia/Ulaanbaatar  # Ulan Bator Time (obsolete)
+UZST    21600 D  # Uzbekistan Summer Time (obsolete)
 UZT     18000    # Uzbekistan Time (obsolete)
 VLAST   Asia/Vladivostok  # Vladivostok Summer Time (obsolete)
 VLAT    Asia/Vladivostok  # Vladivostok Time (obsolete)
@@ -212,8 +179,7 @@ WIT     32400    # Waktu Indonesia Timur (caution: this used to mean 25200)
                  #     (Asia/Jayapura)
 WITA    28800    # Waktu Indonesia Tengah
                  #     (Asia/Makassar)
-XJT     21600    # Xinjiang Time
-                 #     (Asia/Urumqi)
+XJT     21600    # Xinjiang Time (obsolete)
 YAKST   Asia/Yakutsk  # Yakutsk Summer Time (obsolete)
 YAKT    Asia/Yakutsk  # Yakutsk Time (obsolete)
 YEKST   21600 D  # Yekaterinburg Summer Time (obsolete)

src/timezone/tznames/Atlantic.txt

@@ -44,14 +44,10 @@ AST    -14400    # Atlantic Standard Time
                  #     (America/Thule)
                  #     (America/Tortola)
                  #     (Atlantic/Bermuda)
-AZOST       0 D  # Azores Summer Time
-                 #     (Atlantic/Azores)
-AZOT    -3600    # Azores Time
-                 #     (Atlantic/Azores)
-CVT     Atlantic/Cape_Verde  # Cape Verde Time
-                 #     (Atlantic/Cape_Verde)
-FKST    Atlantic/Stanley  # Falkland Islands Summer/Standard Time
-                 #     (Atlantic/Stanley)
+AZOST       0 D  # Azores Summer Time (obsolete)
+AZOT    -3600    # Azores Time (obsolete)
+CVT     Atlantic/Cape_Verde  # Cape Verde Time (obsolete)
+FKST    Atlantic/Stanley  # Falkland Islands Summer/Standard Time (obsolete)
 FKT     Atlantic/Stanley  # Falkland Islands Time (obsolete)
 GMT         0    # Greenwich Mean Time
                  #     (Africa/Abidjan)
@@ -74,8 +70,7 @@ GMT         0    # Greenwich Mean Time
 # CONFLICT! GST is not unique
 # Other timezones:
 # - GST: Gulf Standard Time (Asia)
-GST     -7200    # South Georgia Time (Atlantic)
-                 #     (Atlantic/South_Georgia)
+GST     -7200    # South Georgia Time (Atlantic) (obsolete)
 WEST     3600 D  # Western Europe Summer Time
                  #     (Atlantic/Canary)
                  #     (Atlantic/Faeroe)

src/timezone/tznames/Australia.txt

@@ -16,8 +16,7 @@ ACST    34200    # Australian Central Standard Time
                  #     (Australia/Adelaide)
                  #     (Australia/Broken_Hill)
                  #     (Australia/Darwin)
-ACWST   31500    # Australian Central Western Standard Time
-                 #     (Australia/Eucla)
+ACWST   31500    # Australian Central Western Standard Time (obsolete)
 AESST   39600 D  # Australia Eastern Summer Standard Time (not in IANA database)
 AEDT    39600 D  # Australian Eastern Daylight Time
                  #     (Australia/Brisbane)
@@ -53,10 +52,8 @@ EAST    36000    # East Australian Standard Time (not in IANA database)
 # Other timezones:
 #  - EST: Eastern Standard Time (America)
 EST     36000    # Eastern Standard Time (not in IANA database)
-LHDT    Australia/Lord_Howe  # Lord Howe Daylight Time
-                 #     (Australia/Lord_Howe)
-LHST    37800    # Lord Howe Standard Time
-                 #     (Australia/Lord_Howe)
+LHDT    Australia/Lord_Howe  # Lord Howe Daylight Time (obsolete)
+LHST    37800    # Lord Howe Standard Time (obsolete)
 LIGT    36000    # Melbourne, Australia (not in IANA database)
 NZT     43200    # New Zealand Time (not in IANA database)
 SADT    37800 D  # South Australian Daylight-Saving Time (not in IANA database)

src/timezone/tznames/Europe.txt

@@ -182,10 +182,15 @@ GMT         0    # Greenwich Mean Time
 # - IST: Israel Standard Time (Asia)
 IST      3600 D  # Irish Summer Time
                  #     (Europe/Dublin)
-MEST     7200 D  # Middle Europe Summer Time (not in IANA database)
-MET      3600    # Middle Europe Time (not in IANA database)
+MEST     7200 D  # Middle Europe Summer Time
+                 #     (MET)
+MESZ     7200 D  # Mitteleuropische Sommerzeit (German)
+                 #     (attested in IANA comments though not their code)
+MET      3600    # Middle Europe Time
+                 #     (MET)
 METDST   7200 D  # Middle Europe Summer Time (not in IANA database)
-MEZ      3600    # Mitteleuropische Zeit (German) (not in IANA database)
+MEZ      3600    # Mitteleuropische Zeit (German)
+                 #     (attested in IANA comments though not their code)
 MSD     14400 D  # Moscow Daylight Time (obsolete)
 MSK     Europe/Moscow  # Moscow Time
                  #     (Europe/Moscow)

src/timezone/tznames/Indian.txt

@@ -7,10 +7,8 @@
 # src/timezone/tznames/Indian.txt
 #
 
-CCT     23400    # Cocos Islands Time (Indian Ocean)
-                 #     (Indian/Cocos)
-CXT     25200    # Christmas Island Time (Indian Ocean)
-                 #     (Indian/Christmas)
+CCT     23400    # Cocos Islands Time (Indian Ocean) (obsolete)
+CXT     25200    # Christmas Island Time (Indian Ocean) (obsolete)
 EAT     10800    # East Africa Time
                  #     (Africa/Addis_Ababa)
                  #     (Africa/Asmera)
@@ -23,16 +21,10 @@ EAT     10800    # East Africa Time
                  #     (Indian/Antananarivo)
                  #     (Indian/Comoro)
                  #     (Indian/Mayotte)
-IOT     Indian/Chagos  # British Indian Ocean Territory (Chagos)
-                 #     (Indian/Chagos)
-MUT     14400    # Mauritius Island Time
-                 #     (Indian/Mauritius)
-MUST    18000 D  # Mauritius Island Summer Time
-                 #     (Indian/Mauritius)
-MVT     18000    # Maldives Island Time
-                 #     (Indian/Maldives)
-RET     14400    # Reunion Time
-                 #     (Indian/Reunion)
-SCT     14400    # Seychelles Time
-                 #     (Indian/Mahe)
+IOT     Indian/Chagos  # British Indian Ocean Territory (Chagos) (obsolete)
+MUT     14400    # Mauritius Island Time (obsolete)
+MUST    18000 D  # Mauritius Island Summer Time (obsolete)
+MVT     18000    # Maldives Island Time (obsolete)
+RET     14400    # Reunion Time (obsolete)
+SCT     14400    # Seychelles Time (obsolete)
 TFT     18000    # Kerguelen Time (obsolete)

src/timezone/tznames/Pacific.txt

@@ -10,72 +10,48 @@
 # CONFLICT! BST is not unique
 # Other timezones:
 #  - BST: British Summer Time
-BST     39600    # Bougainville Standard Time (Papua New Guinea)
-                 #     (Pacific/Bougainville)
-CHADT   49500 D  # Chatham Daylight Time (New Zealand)
-                 #     (Pacific/Chatham)
-CHAST   45900    # Chatham Standard Time (New Zealand)
-                 #     (Pacific/Chatham)
+BST     39600    # Bougainville Standard Time (Papua New Guinea) (obsolete)
+CHADT   49500 D  # Chatham Daylight Time (New Zealand) (obsolete)
+CHAST   45900    # Chatham Standard Time (New Zealand) (obsolete)
 ChST    36000    # Chamorro Standard Time (lower case "h" is as in IANA database)
                  #     (Pacific/Guam)
                  #     (Pacific/Saipan)
-CHUT    36000    # Chuuk Time
-                 #     (Pacific/Chuuk)
-CKT     Pacific/Rarotonga  # Cook Islands Time
-                 #     (Pacific/Rarotonga)
-EASST   Pacific/Easter  # Easter Island Summer Time
-                 #     (Pacific/Easter)
+CHUT    36000    # Chuuk Time (obsolete)
+CKT     Pacific/Rarotonga  # Cook Islands Time (obsolete)
+EASST   Pacific/Easter  # Easter Island Summer Time (obsolete)
 # CONFLICT! EAST is not unique
 # Other timezones:
 #  - EAST: East Australian Standard Time (Australia)
-EAST    Pacific/Easter  # Easter Island Time (Chile)
-                 #     (Pacific/Easter)
-FJST    46800 D  # Fiji Summer Time (caution: this used to mean -46800)
-                 #     (Pacific/Fiji)
-FJT     43200    # Fiji Time (caution: this used to mean -43200)
-                 #     (Pacific/Fiji)
-GALT   -21600    # Galapagos Time
-                 #     (Pacific/Galapagos)
-GAMT   -32400    # Gambier Time
-                 #     (Pacific/Gambier)
-GILT    43200    # Gilbert Islands Time
-                 #     (Pacific/Tarawa)
+EAST    Pacific/Easter  # Easter Island Time (Chile) (obsolete)
+FJST    46800 D  # Fiji Summer Time (caution: this used to mean -46800) (obsolete)
+FJT     43200    # Fiji Time (caution: this used to mean -43200) (obsolete)
+GALT   -21600    # Galapagos Time (obsolete)
+GAMT   -32400    # Gambier Time (obsolete)
+GILT    43200    # Gilbert Islands Time (obsolete)
 HST    -36000    # Hawaiian Standard Time
                  #     (Pacific/Honolulu)
                  #     (Pacific/Johnston)
-KOST    Pacific/Kosrae  # Kosrae Time
-                 #     (Pacific/Kosrae)
-LINT    Pacific/Kiritimati  # Line Islands Time (Kiribati)
-                 #     (Pacific/Kiritimati)
-MART   -34200    # Marquesas Time
-                 #     (Pacific/Marquesas)
-MHT     43200    # Kwajalein Time
-                 #     (Pacific/Kwajalein)
-                 #     (Pacific/Majuro)
+KOST    Pacific/Kosrae  # Kosrae Time (obsolete)
+LINT    Pacific/Kiritimati  # Line Islands Time (Kiribati) (obsolete)
+MART   -34200    # Marquesas Time (obsolete)
+MHT     43200    # Kwajalein Time (obsolete)
 MPT     36000    # North Mariana Islands Time (not in IANA database)
-NCT     39600    # New Caledonia Time
-                 #     (Pacific/Noumea)
+NCT     39600    # New Caledonia Time (obsolete)
 # CONFLICT! NFT is not unique
 # Other timezones:
 #  - NFT: Newfoundland Time (America)
-NFT     Pacific/Norfolk  # Norfolk Time
-                 #     (Pacific/Norfolk)
-NRT     Pacific/Nauru  # Nauru Time
-                 #     (Pacific/Nauru)
-NUT     Pacific/Niue  # Niue Time
-                 #     (Pacific/Niue)
+NFT     Pacific/Norfolk  # Norfolk Time (obsolete)
+NRT     Pacific/Nauru  # Nauru Time (obsolete)
+NUT     Pacific/Niue  # Niue Time (obsolete)
 NZDT    46800 D  # New Zealand Daylight Time
                  #     (Antarctica/McMurdo)
                  #     (Pacific/Auckland)
 NZST    43200    # New Zealand Standard Time
                  #     (Antarctica/McMurdo)
                  #     (Pacific/Auckland)
-PGT     36000    # Papua New Guinea Time
-                 #     (Pacific/Port_Moresby)
-PHOT    Pacific/Enderbury  # Phoenix Islands Time (Kiribati)
-                 #     (Pacific/Enderbury)
-PONT    39600    # Ponape Time (Micronesia)
-                 #     (Pacific/Ponape)
+PGT     36000    # Papua New Guinea Time (obsolete)
+PHOT    Pacific/Enderbury  # Phoenix Islands Time (Kiribati) (obsolete)
+PONT    39600    # Ponape Time (Micronesia) (obsolete)
 PST    -28800    # Pacific Standard Time
                  #     (America/Dawson)
                  #     (America/Los_Angeles)
@@ -83,32 +59,21 @@ PST    -28800    # Pacific Standard Time
                  #     (America/Vancouver)
                  #     (America/Whitehorse)
                  #     (Pacific/Pitcairn)
-PWT     32400    # Palau Time
-                 #     (Pacific/Palau)
-SBT     39600    # Solomon Islands Time
-                 #     (Pacific/Guadalcanal)
+PWT     32400    # Palau Time (obsolete)
+SBT     39600    # Solomon Islands Time (obsolete)
 SST    -39600    # South Sumatran Time
                  #     (Pacific/Midway)
                  #     (Pacific/Pago_Pago)
-TAHT   -36000    # Tahiti Time (IANA database says "TAHT", other sources "THAT")
-                 #     (Pacific/Tahiti)
-TKT     Pacific/Fakaofo  # Tokelau Time
-                 #     (Pacific/Fakaofo)
+TAHT   -36000    # Tahiti Time (obsolete)
+TKT     Pacific/Fakaofo  # Tokelau Time (obsolete)
 TOT     46800    # Tonga Time (obsolete)
-TRUT    36000    # Truk Time (IANA database used to say "TRUT", other sources say "TRUK")
-                 #     (Pacific/Truk)
-TVT     43200    # Tuvalu Time
-                 #     (Pacific/Funafuti)
-VUT     39600    # Vanuata Time
-                 #     (Pacific/Efate)
-WAKT    43200    # Wake Time
-                 #     (Pacific/Wake)
-WFT     43200    # Wallis and Futuna Time
-                 #     (Pacific/Wallis)
-WSDT    50400 D  # West Samoa Daylight Time
-                 #     (Pacific/Apia)
-WSST    46800    # West Samoa Standard Time
-                 #     (Pacific/Apia)
+TRUT    36000    # Truk Time (obsolete)
+TVT     43200    # Tuvalu Time (obsolete)
+VUT     39600    # Vanuata Time (obsolete)
+WAKT    43200    # Wake Time (obsolete)
+WFT     43200    # Wallis and Futuna Time (obsolete)
+WSDT    50400 D  # West Samoa Daylight Time (obsolete)
+WSST    46800    # West Samoa Standard Time (obsolete)
 # CONFLICT! WST is not unique
 # Other timezones:
 #  - WST: Western Standard Time (Australia)

src/timezone/tznames/README

@@ -29,6 +29,12 @@ see the `Australia' and `India' files.
 The files named Africa.txt, etc, are not intended to be used directly as
 time zone abbreviation files. They contain reference definitions of time zone
 abbreviations that can be copied into a custom abbreviation file as needed.
-Note that these files (*.txt) are already a subset of the IANA timezone
-database files: we tried to list only those time zone abbreviations that
-(according to the IANA timezone database) appear to be still in use.
+These files contain most of the time zone abbreviations that were shown
+in the IANA timezone database circa 2010.
+
+However, it turns out that many of these abbreviations had simply been
+invented by the IANA timezone group, and do not have currency in real-world
+use.  The IANA group have changed their policy about that, and now prefer to
+use numeric UTC offsets whenever there's not an abbreviation with known
+real-world popularity.  A lot of these abbreviations therefore no longer
+appear in the IANA data, and so are marked "obsolete" in these data files.