$ git clone -n https://github.com/xcp-ng-rpms/gnutls.git /var/lib/mock/v8.3-incoming-10085-28689/root/chroot_tmpdir/scmroot/gnutls
Cloning into '/var/lib/mock/v8.3-incoming-10085-28689/root/chroot_tmpdir/scmroot/gnutls'...
$ git fetch origin 93250c6150e3b44c4d6b4d36181425a6ebfb2823:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/gnutls
 * [new ref]         93250c6150e3b44c4d6b4d36181425a6ebfb2823 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 93250c6 Import gnutls-3.3.29-10.xs8.src.rpm