$ git clone -n https://src.fedoraproject.org/rpms/rubygem-multi_json.git /var/lib/mock/f39-build-1499369-34744/root/chroot_tmpdir/scmroot/rubygem-multi_json
Cloning into '/var/lib/mock/f39-build-1499369-34744/root/chroot_tmpdir/scmroot/rubygem-multi_json'...
$ git fetch origin e138f8a42b6b154f0e66ce34d3fe8a8a8fa16c8b:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rubygem-multi_json
 * [new ref]         e138f8a42b6b154f0e66ce34d3fe8a8a8fa16c8b -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at e138f8a Rebuilt for https://fedoraproject.org/wiki/Fedora_39_Mass_Rebuild