$ git clone -n https://src.fedoraproject.org/rpms/darktable.git /var/lib/mock/f45-build-39828-762/root/chroot_tmpdir/scmroot/darktable
Cloning into '/var/lib/mock/f45-build-39828-762/root/chroot_tmpdir/scmroot/darktable'...
$ git fetch origin 4f4662057d3710fc08e720cb41c24731103bb19a:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/darktable
 * [new ref]         4f4662057d3710fc08e720cb41c24731103bb19a -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 4f46620 Rebuilt for libxml-2.5.4