$ git clone -n https://github.com/xcp-ng-rpms/blktap.git /var/lib/mock/v8.3-v-qcow2-9438-28180/root/chroot_tmpdir/scmroot/blktap
Cloning into '/var/lib/mock/v8.3-v-qcow2-9438-28180/root/chroot_tmpdir/scmroot/blktap'...
$ git fetch origin 534e3858ca0789ec255146b58ff4766cc0d9c8a1:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/blktap
 * [new ref]         534e3858ca0789ec255146b58ff4766cc0d9c8a1 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 534e385 Add QCOW2 support