$ git clone -n https://github.com/xcp-ng-rpms/libevent /var/lib/mock/v8.3-u-pcoval1-9901-28607/root/chroot_tmpdir/scmroot/libevent
Cloning into '/var/lib/mock/v8.3-u-pcoval1-9901-28607/root/chroot_tmpdir/scmroot/libevent'...
$ git fetch origin 8a4e8e616e96e5b0beaccc76e2042e3869c18065:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/libevent
 * [new ref]         8a4e8e616e96e5b0beaccc76e2042e3869c18065 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 8a4e8e6 spec: Bump release and update changelog