$ git clone -n https://src.fedoraproject.org/rpms/frozen.git /var/lib/mock/f45-build-9294-401/root/chroot_tmpdir/scmroot/frozen
Cloning into '/var/lib/mock/f45-build-9294-401/root/chroot_tmpdir/scmroot/frozen'...
$ git fetch origin 3f1c35d4b613577912c6c334ae0674869a2f2ea0:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/frozen
 * [new ref]         3f1c35d4b613577912c6c334ae0674869a2f2ea0 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 3f1c35d Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild