$ git clone -n https://src.fedoraproject.org/rpms/yggdrasil.git /var/lib/mock/f42-build-866858-174190/root/chroot_tmpdir/scmroot/yggdrasil
Cloning into '/var/lib/mock/f42-build-866858-174190/root/chroot_tmpdir/scmroot/yggdrasil'...
$ git fetch origin f9963768bf8da934d8d2bf0e0a32aa29f7a836fe:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/yggdrasil
 * [new ref]         f9963768bf8da934d8d2bf0e0a32aa29f7a836fe -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at f996376 Use systemd_sysusers_compat