$ git clone -n https://github.com/xcp-ng-rpms/xs-opam-repo.git /var/lib/mock/v8.3-u-asultanov2-11384-29693/root/chroot_tmpdir/scmroot/xs-opam-repo
Cloning into '/var/lib/mock/v8.3-u-asultanov2-11384-29693/root/chroot_tmpdir/scmroot/xs-opam-repo'...
$ git fetch origin fd6484b8122deabff58c522750d43c5ede23269f:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/xs-opam-repo
 * [new ref]         fd6484b8122deabff58c522750d43c5ede23269f -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at fd6484b bump release for test build