$ git clone -n https://github.com/xcp-ng-rpms/ca-certificates /var/lib/mock/v8.3-incoming-10976-29394/root/chroot_tmpdir/scmroot/ca-certificates
Cloning into '/var/lib/mock/v8.3-incoming-10976-29394/root/chroot_tmpdir/scmroot/ca-certificates'...
$ git fetch origin d2a69c8260d02ccc165607b4ed4936f01f59a869:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/ca-certificates
 * [new ref]         d2a69c8260d02ccc165607b4ed4936f01f59a869 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at d2a69c8 Import ca-certificates-2021.2.50-73.xs8.src.rpm