$ git clone -n https://github.com/xcp-ng-rpms/libevent /var/lib/mock/v8.3-u-pcoval1-9895-28607/root/chroot_tmpdir/scmroot/libevent
Cloning into '/var/lib/mock/v8.3-u-pcoval1-9895-28607/root/chroot_tmpdir/scmroot/libevent'...
$ git fetch origin 3cd719a7c93787104df598afa5e7300cd1178b6d:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/libevent
 * [new ref]         3cd719a7c93787104df598afa5e7300cd1178b6d -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 3cd719a spec: Bump release and update changelog