$ git clone -n https://github.com/xcp-ng-rpms/gnutls.git /var/lib/mock/v8.3-u-pcoval2-10879-29379/root/chroot_tmpdir/scmroot/gnutls
Cloning into '/var/lib/mock/v8.3-u-pcoval2-10879-29379/root/chroot_tmpdir/scmroot/gnutls'...
$ git fetch origin d7ae67db150e5b540bb7ea26390a67677bd9de32:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/gnutls
 * [new ref]         d7ae67db150e5b540bb7ea26390a67677bd9de32 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at d7ae67d bump release for test build