$ git clone -n https://github.com/xcp-ng-rpms/libevent.git /var/lib/mock/v8.3-incoming-9076-27934/root/chroot_tmpdir/scmroot/libevent
Cloning into '/var/lib/mock/v8.3-incoming-9076-27934/root/chroot_tmpdir/scmroot/libevent'...
$ git fetch origin 8f7f53e1b13cbe54d45fec57317d3c1a4a1e695c:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/libevent
 * [new ref]         8f7f53e1b13cbe54d45fec57317d3c1a4a1e695c -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 8f7f53e Import libevent-2.0.21-5.xs8.src.rpm