As mentioned in Lessons Learned Packaging PostGIS extensions, I am working on PostGIS 2.0.0 extension packaging. One of the things I wanted to know was what objects, types, functions etc were installed by my extension. The new packaging system allows for cataloging this relatively easily, but I couldn't find a function or view for this and didn't see one mentioned in the manual, so I created this query which seems to work pretty well as far as I can tell. The basic idea being that any object that an extension depends on that is not an extension is part of the extension package.

SELECT c.relname As item_type, 
    COALESCE(proc.proname,typ.typname, cd.relname, op.oprname, 
        'CAST(' || cs.typname || ' AS ' || ct.typname || ') ', opcname, opfname) As item_name,
    COALESCE(proc.proisagg,false) As is_agg, oidvectortypes(proc.proargtypes) As arg_types
FROM pg_depend As d INNER JOIN pg_extension As e
    ON d.refobjid = e.oid INNER JOIN pg_class As c ON
        c.oid = d.classid
        LEFT JOIN pg_proc AS proc ON proc.oid = d.objid
        LEFT JOIN pg_type AS typ ON typ.oid = d.objid
        LEFT JOIN pg_class As cd ON cd.oid = d.objid
        LEFT JOIN pg_operator As op ON op.oid = d.objid
        LEFT JOIN pg_cast AS ca ON ca.oid = d.objid
        LEFT JOIN pg_type AS cs ON ca.castsource = cs.oid
        LEFT JOIN pg_type AS ct ON ca.casttarget = ct.oid
        LEFT JOIN pg_opclass As oc ON oc.oid = d.objid
        LEFT JOIN pg_opfamily As ofa ON ofa.oid = d.objid
WHERE d.deptype = 'e' and e.extname = 'postgis'
ORDER BY item_type, item_name;

The output looks like:

 item_type  |            item_name             | is_agg |arg_types
------------+----------------------------------+--------+-----------
pg_cast     | CAST(box2d AS box3d)             | f      |
pg_cast     | CAST(box2d AS geometry)          | f      |
pg_cast     | CAST(box3d AS box)               | f      |
pg_cast     | CAST(box3d AS box2d)             | f      |
pg_cast     | CAST(box3d AS geometry)          | f      |
:
pg_opclass  | btree_geography_ops              | f      |
pg_opclass  | btree_geometry_ops               | f      |
pg_opclass  | gist_geography_ops               | f      |
pg_opclass  | gist_geometry_ops_2d             | f      |
pg_opclass  | gist_geometry_ops_nd             | f      |
:
pg_opfamily | btree_geography_ops              | f      |
pg_opfamily | btree_geometry_ops               | f      |
pg_opfamily | gist_geography_ops               | f      |
pg_opfamily | gist_geometry_ops_2d             | f      |
pg_opfamily | gist_geometry_ops_nd             | f      |
:
pg_operator | &&                               | f      |
pg_operator | &&&                              | f      |
:
pg_proc     | postgis_addbbox                  | f      | geometry
:
pg_type     | spheroid                         | f      |
pg_type     | summarystats                     | f      |
:
pg_type     | wktgeomval                       | f      |
(984 rows)