I must not understand the permissions system

 From both User A and User B, this query returns rows:

select * from pg_trigger where tgname = '<name>'

but User A gets 2 rows (because I have the same trigger name on two
different tables) while User B only sees one of them.  Is it permissions
on pg_trigger or on the original table (or some other thing) that is
preventing B from seeing that row?