$ git clone -n https://src.fedoraproject.org/rpms/gnutls.git /var/lib/mock/f40-build-1463765-23595/root/chroot_tmpdir/scmroot/gnutls
Cloning into '/var/lib/mock/f40-build-1463765-23595/root/chroot_tmpdir/scmroot/gnutls'...
$ git fetch origin 1203838c81b0ed72a1591829e4f65a7dd012b4a8:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/gnutls
 * [new ref]         1203838c81b0ed72a1591829e4f65a7dd012b4a8 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 1203838 Update to 3.8.6 upstream release