$ git clone -n https://src.fedoraproject.org/rpms/perl-Test-Spec.git /var/lib/mock/f45-build-26850-619/root/chroot_tmpdir/scmroot/perl-Test-Spec
Cloning into '/var/lib/mock/f45-build-26850-619/root/chroot_tmpdir/scmroot/perl-Test-Spec'...
$ git fetch origin aa1a3d8ee5497db2878a1676757dd897918d0aea:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/perl-Test-Spec
 * [new ref]         aa1a3d8ee5497db2878a1676757dd897918d0aea -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at aa1a3d8 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild