$ git clone -n https://github.com/xcp-ng-rpms/xs-opam-repo.git /var/lib/mock/v8.3-u-asultanov2-10324-28890/root/chroot_tmpdir/scmroot/xs-opam-repo
Cloning into '/var/lib/mock/v8.3-u-asultanov2-10324-28890/root/chroot_tmpdir/scmroot/xs-opam-repo'...
$ git fetch origin 7cbd400136c40ff8644d74c1f04d6a74bc72d8f7:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/xs-opam-repo
 * [new ref]         7cbd400136c40ff8644d74c1f04d6a74bc72d8f7 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 7cbd400 bump release for test build