dpns-listusrmap(1) on Linux
The text 097bc710f5f9, as Debian 10 (Buster), Debian 9 (Stretch), Debian 8 (Jessie), Debian 7 (Wheezy), Debian 6.0 (Squeeze) shipped it. The page shows this text now.
query about a given user or list all existing users in virtual uid table