$ git clone -n https://github.com/xcp-ng-rpms/gnutls /var/lib/mock/v8.3-incoming-10682-29233/root/chroot_tmpdir/scmroot/gnutls
Cloning into '/var/lib/mock/v8.3-incoming-10682-29233/root/chroot_tmpdir/scmroot/gnutls'...
$ git fetch origin b8bfecfba4c9567e6d654ba1c44339d3c267f580:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/gnutls
 * [new ref]         b8bfecfba4c9567e6d654ba1c44339d3c267f580 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at b8bfecf Merge pull request #1 from xcp-ng-rpms/8.3-XS-1557