howto/rename-a-user: add hint about other repos

howto/rename-a-user.md

@@ -40,3 +40,8 @@ If a new account is created as part or the renaming process, it's possible to
 however untested, and TPA doesn't have access to the hosted Nextcloud CLI.
 
 [files:transfer-ownership]: https://docs.nextcloud.com/server/latest/admin_manual/configuration_server/occ_command.html#transfer
+
+# Other
+
+It's a good idea to grep the `tor-puppet.git` repository, this can catch
+instances of the old username existing in places like `/etc/subuid`.