schema access privs

What does the results in col 'List of schemas Access privileges'
indicate?  Are those three results split by the '/' char?  What
are the three sections?  What is 'postgres+'

Can't find this explained in the docs.

template1-# \dn+ pg_catalog
                           List of schemas
    Name    |  Owner   |  Access privileges   |      Description
------------+----------+----------------------+-----------------------
 pg_catalog | postgres | postgres=UC/postgres+| system catalog schema
            |          | =U/postgres          |
(1 row)

http://www.postgresql.org/docs/current/static/app-psql.html

\dn[+] [ pattern ]

    Lists schemas (namespaces). If pattern is specified, only schemas
    whose names match the pattern are listed. Non-local temporary schemas
    are suppressed. If + is appended to the command name, each object
    is listed with its associated permissions and description, if any.