-: restore *old* group as *new* group. Specifying "" for *new* will
- clear the group, i.e. `--map-user foo=`.
+: for every path, restore the *old* (saved) group name as *new*.
+ Specifying "" for *new* will clear the group. For example
+ "--map-group foo=" will allow the gid to take effect for any path
+ that originally had a group of "foo", unless countermanded by a
+ subsequent "--map-group foo=..." specification. See DESCRIPTION
+ above for further information.