$ git clone -n https://github.com/xcp-ng-rpms/xs-opam-repo /var/lib/mock/v9.0-u-ydi1-11217-29596/root/chroot_tmpdir/scmroot/xs-opam-repo
Cloning into '/var/lib/mock/v9.0-u-ydi1-11217-29596/root/chroot_tmpdir/scmroot/xs-opam-repo'...
$ git fetch origin bde77434425c3b16dee8b1a0cdf38d12ff34b181:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/xs-opam-repo
 * [new ref]         bde77434425c3b16dee8b1a0cdf38d12ff34b181 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at bde7743 bump release for test build