$ git clone -n https://github.com/xcp-ng-rpms/xs-opam-repo /var/lib/mock/v8.3-u-psafont1-10269-28847/root/chroot_tmpdir/scmroot/xs-opam-repo
Cloning into '/var/lib/mock/v8.3-u-psafont1-10269-28847/root/chroot_tmpdir/scmroot/xs-opam-repo'...
$ git fetch origin ada0d1ee6476166604ef7ba9742cabc46f317b85:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/xs-opam-repo
 * [new ref]         ada0d1ee6476166604ef7ba9742cabc46f317b85 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at ada0d1e bump release for test build