$ git clone -n https://github.com/xcp-ng-rpms/libevent /var/lib/mock/v8.3-u-pcoval1-9903-28607/root/chroot_tmpdir/scmroot/libevent
Cloning into '/var/lib/mock/v8.3-u-pcoval1-9903-28607/root/chroot_tmpdir/scmroot/libevent'...
$ git fetch origin 31abfb8ab0ee0665135ff73a4c4497a72f2a9022:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/libevent
 * [new ref]         31abfb8ab0ee0665135ff73a4c4497a72f2a9022 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 31abfb8 spec: Bump release and update changelog