$ git clone -n https://github.com/xcp-ng-rpms/kernel.git /var/lib/mock/v8.3-u-qcasasnovas1-9841-28559/root/chroot_tmpdir/scmroot/kernel
Cloning into '/var/lib/mock/v8.3-u-qcasasnovas1-9841-28559/root/chroot_tmpdir/scmroot/kernel'...
$ git fetch origin b9548355ef5f758971fe092978a2a5ae68417253:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/kernel
 * [new ref]             b9548355ef5f758971fe092978a2a5ae68417253 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at b9548355e bump release for test build