It's a new feature that's available on the main branch, but not on join-test.codeberg.org ~n
https://codeberg.org/Codeberg-e.V./registration-server/commit/c04e600309ee874c37022112ea58f79fbdf4bc04
https://codeberg.org/Codeberg-e.V./registration-server/commit/c04e600309ee874c37022112ea58f79fbdf4bc04