Allowed timezone values

I am playing with our allowed timezone settings and saw a few strange
things. It understands "EST5EDT", but how does it understand "XYT5ABT"?

test=> set timezone = 'XYT5ABT';
SET

test=> SELECT current_timestamp;
now
------------------------------
2005-10-13 12:48:39.59164-04
(1 row)

test=> SELECT current_timestamp + '3 months';
?column?
-------------------------------
2006-01-13 12:48:32.765068-05
(1 row)

(Shouldn't current_timestamp's label be "current_timestamp", and not
"now"?)

Also, JST doesn't work anymore, but JST9 does. JST has no daylight
savings time values, so it is a valid timezone setting, while EST is
not:

test=> set timezone = 'JST';
ERROR: unrecognized time zone name: "JST"

test=> set timezone = 'JST9';
SET

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Bruce Momjian | http://candle.pha.pa.us
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