$ git clone -n https://src.fedoraproject.org/rpms/xmbdfed.git /var/lib/mock/f45-build-38938-730/root/chroot_tmpdir/scmroot/xmbdfed
Cloning into '/var/lib/mock/f45-build-38938-730/root/chroot_tmpdir/scmroot/xmbdfed'...
$ git fetch origin 21534a422d185785f8af28377cd6c4c18676c04d:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/xmbdfed
 * [new ref]         21534a422d185785f8af28377cd6c4c18676c04d -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 21534a4 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild