$ git clone -n https://src.fedoraproject.org/rpms/mrcpp.git /var/lib/mock/f45-build-19240-545/root/chroot_tmpdir/scmroot/mrcpp
Cloning into '/var/lib/mock/f45-build-19240-545/root/chroot_tmpdir/scmroot/mrcpp'...
$ git fetch origin 1f8d389bfd0ed951682909a19f40f189dd9c807c:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/mrcpp
 * [new ref]         1f8d389bfd0ed951682909a19f40f189dd9c807c -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 1f8d389 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild