$ git clone -n https://github.com/xcp-ng-rpms/blktap.git /var/lib/mock/v8.3-v-qcow2-9034-27919/root/chroot_tmpdir/scmroot/blktap
Cloning into '/var/lib/mock/v8.3-v-qcow2-9034-27919/root/chroot_tmpdir/scmroot/blktap'...
$ git fetch origin 205e190ea5789dfec466bb5b8a89a785852afd44:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/blktap
 * [new ref]         205e190ea5789dfec466bb5b8a89a785852afd44 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 205e190 Add QCOW2 support