On 9/10/21 1:00 AM, Danilo Spinella via tz wrote:

I have noticed that the format for the zone Asia/Bangkok is shown as "+07" instead of Indochina Time (ICT), Western Indonesian Time (WIB) or Thailand Standard Time (THA). Is this because none of the above is standard?

Yes, as far as we know there is no widely-used English-language abbreviation for time in that timezone. Long ago when POSIX required an acronym for each time zone, I invented "ICT" to fill in the blank spot for Asia/Bangkok etc. After POSIX relaxed that requirement it was changed in tzdb to "+07" which is what it probably should have been in the first place.