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.