Where to document system views?

I have noticed that there is a nearly total lack of documentation of the
various predefined system views, which as of 7.2 include:

    pg_indexes
    pg_rules
    pg_stat_activity
    pg_stat_all_indexes
    pg_stat_all_tables
    pg_stat_database
    pg_stat_sys_indexes
    pg_stat_sys_tables
    pg_stat_user_indexes
    pg_stat_user_tables
    pg_statio_all_indexes
    pg_statio_all_sequences
    pg_statio_all_tables
    pg_statio_sys_indexes
    pg_statio_sys_sequences
    pg_statio_sys_tables
    pg_statio_user_indexes
    pg_statio_user_sequences
    pg_statio_user_tables
    pg_stats
    pg_tables
    pg_user
    pg_views

The lack of docs for the pg_stat* stuff can be blamed on Jan and me,
but the other ones are of longer standing.  My current thought is to
add a section somewhere that describes these views, but where?  I don't
think it's quite right to document them under the System Catalogs
chapter of the Developer's Guide, since they're all intended for use
by ordinary users and dbadmins; the system itself doesn't use them.
Thoughts?

            regards, tom lane