$ git clone -n https://github.com/xcp-ng-rpms/gnutls.git /var/lib/mock/v8.3-u-pcoval2-10602-29157/root/chroot_tmpdir/scmroot/gnutls
Cloning into '/var/lib/mock/v8.3-u-pcoval2-10602-29157/root/chroot_tmpdir/scmroot/gnutls'...
$ git fetch origin 9106561d44f7cd6df3c11cba168a572250a4fa60:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/gnutls
 * [new ref]         9106561d44f7cd6df3c11cba168a572250a4fa60 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 9106561 bump release for test build