Minor Description
The following line is in the "EXAMPLES" section:
# lctl nodemap_modify --name remotesite --property map_mode --value uid_only
While that does set nodemap.remotesite.map_mode=uid as one might expect, the following can also be called:
# lctl nodemap_modify --name remotesite --property map_mode --value uid_only,gid
which will set nodemap.remotesite.map_mode=uid,gid
The man page should only list "uid", "gid" and "projid" as valid values, if the string processing by the kernel was more strict "uid_only" should be an error as an invalid value.