$ git clone -n https://github.com/xcp-ng-rpms/xapi.git /var/lib/mock/v8.3-incoming-11314-29646/root/chroot_tmpdir/scmroot/xapi
Cloning into '/var/lib/mock/v8.3-incoming-11314-29646/root/chroot_tmpdir/scmroot/xapi'...
$ git fetch origin 5f9a8c77b0d459b82d8fd8cb1ff7e02431d29ec9:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/xapi
 * [new ref]         5f9a8c77b0d459b82d8fd8cb1ff7e02431d29ec9 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 5f9a8c7 Fix QCOW2-backed VDI snapshots not being exported properly