This might belong in lj_userdoc or
lj_sysdoc but I'll post here anyway:
On http://www.livejournal.com/doc/server/ the following bit of code appears (on display):
dbweights - The <dbtblref tblid="dbinfo">dbinfo</dbtblref> table keeps track of which databases exist. This ones keeps track of each database's roles and weights.
I'd have thought from looking at the DTD that <dbtblref> was meant to be a link to somewhere else? (Like the relevant table?)