$ git clone -n https://github.com/xcp-ng-rpms/ca-certificates /var/lib/mock/v8.3-u-pcoval2-11032-29465/root/chroot_tmpdir/scmroot/ca-certificates
Cloning into '/var/lib/mock/v8.3-u-pcoval2-11032-29465/root/chroot_tmpdir/scmroot/ca-certificates'...
$ git fetch origin 6721b40aaf20ea53f1d1a75e1a68d1442d3bef9d:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/ca-certificates
 * [new ref]         6721b40aaf20ea53f1d1a75e1a68d1442d3bef9d -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 6721b40 bump release for test build