$ git clone -n https://github.com/xcp-ng-rpms/xs-opam-repo.git /var/lib/mock/v8.3-u-asultanov2-9200-27999/root/chroot_tmpdir/scmroot/xs-opam-repo
Cloning into '/var/lib/mock/v8.3-u-asultanov2-9200-27999/root/chroot_tmpdir/scmroot/xs-opam-repo'...
$ git fetch origin a425a64bac2a54a3c3011a021707d2e37f4ea371:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/xs-opam-repo
 * [new ref]         a425a64bac2a54a3c3011a021707d2e37f4ea371 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at a425a64 bump release for test build