Ronaldo Vasconcellos <ronaldo@cais.rnp.br> writes:
http://www.tldp.org/HOWTO/TimePrecision-HOWTO/tz.html#tz.examples
[I'll CC: this message to Avi Alkalay, who maintains that web page, so that he can correct its time zone abbreviations as he sees fit.] As far as I can see, the abbreviations used in the above-referenced table are merely examples and are not meant to be recommendations. Abbreviations like "BRDT" would not correspond to common Brazilian practice, which is to use the Portuguese equivalent of "summer time" rather than "daylight time". As is stated in the tz tables' comments, in 1999 I invented the abbreviations BRT/BRST, AMT/AMST, etc., that are used in the current tz tables for Brazil. As far as I know nobody else has needed, or uses, English-language acronyms for the Brazilian time zone. However, should an alternate tradition arise in practice, of course we'd prefer to use the English-language abbreviations that people are actually using, as opposed to abbreviations that we have invented.