wrstuden@netbsd.org said:
> Who is the central repository for these values? 

When I investigated for choosing a new partition ID
for NetBSD (~1998), the most comprehensive sources were
the "How it works" documents by Hale Landis and the
famous "Ralph Brown interrupt list".

Just tried "google": the "How it works" site  is
http://www.ata-atapi.com/hiw.htm.
It recommends
http://www.win.tue.nl/~aeb/partitions/partition_types-1.html
as the best list of partition identifiers.

best regards
Matthias