[tz] Reason for removal of several TZ abbreviations

[J Andrew Lipscomb]

> Le 4 déc. 2017 à 18:18, Michael Douglass <mikeadouglass at gmail.com> a écrit :
> Exactly - that's why I said opaque

I just came up with a system I think is opaque enough while still maintaining a bit of useful information in the id:
First up, it goes with the letter-digit-letter format.

The first letter represents the (lower) GMT offset of the zone in military format.
(This represents the one real flaw I see: a zone’s proper letter can change if it adopts something on the order of year-round daylight savings time.)

The digit is usually 0. It changes in the following cases:
3 would indicate a +:15 zone if there were any, 5 is a +:30 zone, and 8 is a +:45 zone.
1 is used with M (normally +12) to indicate +13, and M2 similarly indicates +14.
1 is also used with other letters when the 0 range overflows.

The second letter is meaningless UNLESS it is Z. Z indicates a non-geographic time zone (the Etc/ series of indicators).

The list I just randomized, presented in order of newID:

Africa/Ndjamena	a0a
Africa/Tunis	a0b
Europe/Gibraltar	a0c
Europe/Monaco	a0d
Europe/Oslo	a0e
Europe/Warsaw	a0f
Europe/Zurich	a0g
Europe/Madrid	a0h
Europe/Copenhagen	a0i
Europe/Brussels	a0j
Europe/Malta	a0k
Europe/Andorra	a0l
Africa/Algiers	a0m
Europe/Paris	a0n
Europe/Amsterdam	a0o
Europe/Luxembourg	a0p
Africa/Ceuta	a0q
Europe/Tirane	a0r
Europe/Vienna	a0s
Europe/Belgrade	a0t
Europe/Budapest	a0u
Europe/Prague	a0v
Europe/Rome	a0w
Africa/Lagos	a0x
Europe/Stockholm	a0y
Etc/GMT-1	a0z
Asia/Beirut	b0a
Europe/Bucharest	b0b
Europe/Riga	b0c
Africa/Khartoum	b0d
Asia/Damascus	b0e
Africa/Windhoek	b0f
Europe/Tallinn	b0g
Asia/Hebron	b0h
Africa/Maputo	b0i
Europe/Athens	b0j
Europe/Kiev	b0k
Europe/Sofia	b0l
Africa/Johannesburg	b0m
Europe/Chisinau	b0n
Europe/Zaporozhye	b0o
Asia/Famagusta	b0p
Asia/Nicosia	b0q
Africa/Tripoli	b0r
Europe/Uzhgorod	b0s
Asia/Jerusalem	b0t
Africa/Cairo	b0u
Asia/Amman	b0v
Asia/Gaza	b0w
Europe/Helsinki	b0x
Europe/Kaliningrad	b0y
Etc/GMT-2	b0z
Europe/Vilnius	b1a
Europe/Minsk	c0a
Europe/Kirov	c0b
Africa/Nairobi	c0c
Antarctica/Syowa	c0d
Asia/Baghdad	c0e
Asia/Riyadh	c0f
Asia/Qatar	c0g
Europe/Istanbul	c0h
Africa/Juba	c0i
Europe/Moscow	c0j
Europe/Volgograd	c0k
Etc/GMT-3	c0z
Asia/Tehran	c5a
Asia/Tbilisi	d0a
Europe/Saratov	d0b
Asia/Dubai	d0c
Europe/Samara	d0d
Indian/Reunion	d0e
Europe/Astrakhan	d0f
Indian/Mahe	d0g
Asia/Baku	d0h
Europe/Ulyanovsk	d0i
Asia/Yerevan	d0j
Indian/Mauritius	d0k
Etc/GMT-4	d0z
Asia/Kabul	d5a
Asia/Samarkand	e0a
Asia/Aqtobe	e0b
Asia/Oral	e0c
Asia/Dushanbe	e0d
Asia/Karachi	e0e
Asia/Aqtau	e0f
Indian/Kerguelen	e0g
Asia/Yekaterinburg	e0h
Asia/Ashgabat	e0i
Asia/Tashkent	e0j
Antarctica/Mawson	e0k
Asia/Atyrau	e0l
Indian/Maldives	e0m
Etc/GMT-5	e0z
Asia/Colombo	e5a
Asia/Kathmandu	e8a
Asia/Omsk	f0a
Asia/Dhaka	f0b
Antarctica/Vostok	f0c
Asia/Bishkek	f0d
Asia/Almaty	f0e
Asia/Thimphu	f0f
Asia/Urumqi	f0g
Asia/Qyzylorda	f0h
Indian/Chagos	f0i
Etc/GMT-6	f0z
Asia/Yangon	f5a
Indian/Cocos	f5b
Asia/Pontianak	g0a
Asia/Tomsk	g0b
Asia/Bangkok	g0c
Asia/Hovd	g0d
Asia/Novokuznetsk	g0e
Asia/Jakarta	g0f
Asia/Krasnoyarsk	g0g
Antarctica/Davis	g0h
Asia/Barnaul	g0i
Asia/Novosibirsk	g0j
Indian/Christmas	g0k
Asia/Ho_Chi_Minh	g0l
Etc/GMT-7	g0z
Asia/Singapore	h0a
Asia/Taipei	h0b
Asia/Makassar	h0c
Asia/Brunei	h0d
Asia/Kuching	h0e
Asia/Ulaanbaatar	h0f
Asia/Kuala_Lumpur	h0g
Asia/Choibalsan	h0h
Asia/Shanghai	h0i
Asia/Macau	h0j
Asia/Irkutsk	h0k
Asia/Hong_Kong	h0l
Asia/Manila	h0m
Australia/Perth	h0n
Etc/GMT-8	h0z
Asia/Pyongyang	h5a
Australia/Eucla	h8a
Pacific/Palau	i0a
Asia/Khandyga	i0b
Asia/Seoul	i0c
Asia/Yakutsk	i0d
Asia/Dili	i0e
Asia/Chita	i0f
Asia/Jayapura	i0g
Asia/Tokyo	i0h
Etc/GMT-9	i0z
Australia/Adelaide	i5a
Australia/Darwin	i5b
Australia/Broken_Hill	i5c
Australia/Brisbane	k0a
Pacific/Port_Moresby	k0b
Australia/Hobart	k0c
Australia/Sydney	k0d
Australia/Currie	k0e
Asia/Vladivostok	k0f
Australia/Lindeman	k0g
Australia/Melbourne	k0h
Asia/Ust-Nera	k0i
Antarctica/DumontDUrville	k0j
Pacific/Guam	k0k
Pacific/Chuuk	k0l
Etc/GMT-10	k0z
Australia/Lord_Howe	k5a
Pacific/Bougainville	l0a
Pacific/Norfolk	l0b
Antarctica/Macquarie	l0c
Pacific/Kosrae	l0d
Asia/Sakhalin	l0e
Pacific/Noumea	l0f
Pacific/Guadalcanal	l0g
Asia/Magadan	l0h
Pacific/Efate	l0i
Asia/Srednekolymsk	l0j
Antarctica/Casey	l0k
Pacific/Pohnpei	l0l
Etc/GMT-11	l0z
Pacific/Tarawa	m0a
Pacific/Nauru	m0b
Pacific/Majuro	m0c
Pacific/Fiji	m0d
Pacific/Kwajalein	m0e
Pacific/Wallis	m0f
Asia/Anadyr	m0g
Pacific/Wake	m0h
Pacific/Funafuti	m0i
Asia/Kamchatka	m0j
Pacific/Auckland	m0k
Etc/GMT-12	m0z
Pacific/Tongatapu	m1a
Pacific/Fakaofo	m1b
Pacific/Enderbury	m1c
Pacific/Apia	m1d
Etc/GMT-13	m1z
Pacific/Kiritimati	m2a
Etc/GMT-14	m2z
Pacific/Chatham	m8a
Atlantic/Cape_Verde	n0a
Atlantic/Azores	n0b
America/Scoresbysund	n0c
Etc/GMT+1	n0z
America/Noronha	o0a
Atlantic/South_Georgia	o0b
Etc/GMT+2	o0z
America/Argentina/La_Rioja	p0a
America/Argentina/Catamarca	p0b
America/Montevideo	p0c
America/Argentina/Buenos_Aires	p0d
Antarctica/Rothera	p0e
America/Argentina/San_Juan	p0f
America/Sao_Paulo	p0g
America/Godthab	p0h
America/Araguaina	p0i
America/Argentina/Salta	p0j
America/Argentina/Mendoza	p0k
America/Santarem	p0l
America/Cayenne	p0m
America/Argentina/Tucuman	p0n
America/Argentina/Jujuy	p0o
Atlantic/Stanley	p0p
America/Argentina/Cordoba	p0q
America/Miquelon	p0r
America/Argentina/San_Luis	p0s
America/Belem	p0t
America/Maceio	p0u
America/Argentina/Ushuaia	p0v
America/Recife	p0w
America/Paramaribo	p0x
America/Bahia	p0y
Etc/GMT+3	p0z
America/Fortaleza	p1a
America/Argentina/Rio_Gallegos	p1b
America/St_Johns	p5a
America/Blanc-Sablon	q0a
America/Grand_Turk	q0b
America/Goose_Bay	q0c
America/Glace_Bay	q0d
America/Guyana	q0e
America/Porto_Velho	q0f
America/Boa_Vista	q0g
America/Thule	q0h
America/Caracas	q0i
Atlantic/Bermuda	q0j
America/Martinique	q0k
America/Port_of_Spain	q0l
America/Campo_Grande	q0m
America/Halifax	q0n
America/Barbados	q0o
America/Moncton	q0p
America/Manaus	q0q
America/Santiago	q0r
America/La_Paz	q0s
America/Curacao	q0t
America/Santo_Domingo	q0u
America/Puerto_Rico	q0v
America/Asuncion	q0w
America/Cuiaba	q0x
Etc/GMT+4	q0z
America/Cancun	r0a
America/Jamaica	r0b
America/Kentucky/Louisville	r0c
America/Rio_Branco	r0d
America/Indiana/Marengo	r0e
America/Kentucky/Monticello	r0f
America/Lima	r0g
America/Indiana/Winamac	r0h
America/Indiana/Indianapolis	r0i
America/New_York	r0j
America/Indiana/Vevay	r0k
America/Nipigon	r0l
America/Detroit	r0m
America/Guayaquil	r0n
America/Thunder_Bay	r0o
America/Panama	r0p
America/Iqaluit	r0q
America/Indiana/Vincennes	r0r
America/Bogota	r0s
America/Eirunepe	r0t
America/Atikokan	r0u
America/Indiana/Petersburg	r0v
America/Port-au-Prince	r0w
America/Nassau	r0x
America/Toronto	r0y
Etc/GMT+5	r0z
America/Havana	r1a
America/Pangnirtung	r1b
America/Chicago	s0a
America/Resolute	s0b
America/Bahia_Banderas	s0c
America/North_Dakota/Beulah	s0d
America/Swift_Current	s0e
America/North_Dakota/Center	s0f
America/Winnipeg	s0g
America/El_Salvador	s0h
America/Indiana/Tell_City	s0i
America/Mexico_City	s0j
America/Costa_Rica	s0k
America/Monterrey	s0l
America/Tegucigalpa	s0m
America/Managua	s0n
America/Merida	s0o
America/Menominee	s0p
America/Rankin_Inlet	s0q
America/Belize	s0r
Pacific/Galapagos	s0s
America/Regina	s0t
America/Indiana/Knox	s0u
America/North_Dakota/New_Salem	s0v
Pacific/Easter	s0w
America/Rainy_River	s0x
America/Guatemala	s0y
Etc/GMT+6	s0z
America/Matamoros	s1a
America/Edmonton	t0a
America/Chihuahua	t0b
America/Inuvik	t0c
America/Cambridge_Bay	t0d
America/Mazatlan	t0e
America/Hermosillo	t0f
America/Fort_Nelson	t0g
America/Boise	t0h
America/Yellowknife	t0i
America/Creston	t0j
America/Denver	t0k
America/Dawson_Creek	t0l
America/Phoenix	t0m
America/Ojinaga	t0n
Etc/GMT+7	t0z
America/Tijuana	u0a
America/Los_Angeles	u0b
Pacific/Pitcairn	u0c
America/Vancouver	u0d
America/Whitehorse	u0e
America/Dawson	u0f
Etc/GMT+8	u0z
America/Metlakatla	v0a
America/Anchorage	v0b
America/Juneau	v0c
America/Sitka	v0d
Pacific/Gambier	v0e
America/Yakutat	v0f
America/Nome	v0g
Etc/GMT+9	v0z
Pacific/Marquesas	v5a
Pacific/Rarotonga	w0a
Pacific/Tahiti	w0b
Pacific/Honolulu	w0c
America/Adak	w0d
Etc/GMT+10	w0z
Pacific/Pago_Pago	x0a
Pacific/Niue	x0b
Etc/GMT+11	x0z
Etc/GMT+12	y0z
Europe/Dublin	z0a
Africa/Abidjan	z0b
Atlantic/Faroe	z0c
Africa/Bissau	z0d
Atlantic/Madeira	z0e
Africa/Accra	z0f
Africa/Casablanca	z0g
Atlantic/Reykjavik	z0h
America/Danmarkshavn	z0i
Atlantic/Canary	z0j
Europe/Lisbon	z0k
Africa/Monrovia	z0l
Africa/El_Aaiun	z0m
Europe/London	z0n
Etc/UTC	z0z
Etc/GMT	z0z