$ git clone -n https://github.com/xcp-ng-rpms/blktap.git /var/lib/mock/v8.3-v-qcow2-10783-29302/root/chroot_tmpdir/scmroot/blktap
Cloning into '/var/lib/mock/v8.3-v-qcow2-10783-29302/root/chroot_tmpdir/scmroot/blktap'...
$ git fetch origin 6ba31f8006819d573a5182e2d1ab2140364d3676:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/blktap
 * [new ref]         6ba31f8006819d573a5182e2d1ab2140364d3676 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 6ba31f8 Add QCOW2 support