$ git clone -n https://github.com/xcp-ng-rpms/xs-opam-repo.git /var/lib/mock/v8.3-u-asultanov2-11401-29713/root/chroot_tmpdir/scmroot/xs-opam-repo
Cloning into '/var/lib/mock/v8.3-u-asultanov2-11401-29713/root/chroot_tmpdir/scmroot/xs-opam-repo'...
$ git fetch origin 5cab378e2fa57ffc28c8f1e120b7c234549c59fe:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/xs-opam-repo
 * [new ref]         5cab378e2fa57ffc28c8f1e120b7c234549c59fe -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 5cab378 bump release for test build