$ git clone -n https://src.fedoraproject.org/rpms/gnutls.git /var/lib/mock/f41-build-1021103-18021/root/chroot_tmpdir/scmroot/gnutls
Cloning into '/var/lib/mock/f41-build-1021103-18021/root/chroot_tmpdir/scmroot/gnutls'...
$ git fetch origin 87c3926250cad0cfe78e198c35e05ac98aaec826:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/gnutls
 * [new ref]         87c3926250cad0cfe78e198c35e05ac98aaec826 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 87c3926 Bump release to build against newer nettle