They appear to be the region IDs from the time zone file, e.g. $ORACLE_HOME/oracore/zoneinfo/timezone_14.dat
.
In this SQL Fiddle, a value with time zone region PST8PDT
has the last two bytes stood as 0x83
, 0x64
; which matches the values suggested by MOS document ID 414590.1.
I can't see any reference that lists all the possible values, or any obvious way to examine the time zone file. It doesn't seem to be documented, which isn't unreasonable for an internal format. You could figure out values you're interested in, or all values, using the same method but I'm not sure why you'd want to.
There's another support document you might find useful, 340512.1, which is a FAQ about timestamps and time zones.
To convert a region name to an offset value you can use the tz_offs
function, but it uses the current date - so the answer you get will depend on whether you ask in the winter or summer. To get the offset for a certain date you need to compare that timestamp with a UTC timestamp. And you can't really go the other way, as multiple time zone regions map the same offset.