$ git clone -n https://src.fedoraproject.org/rpms/pioneer.git /var/lib/mock/f38-build-side-42-init-devel-637782-26384/root/chroot_tmpdir/scmroot/pioneer
Cloning into '/var/lib/mock/f38-build-side-42-init-devel-637782-26384/root/chroot_tmpdir/scmroot/pioneer'...
$ git fetch origin 07f7609270e7354f059c02d58fd55554f62d5e83:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/pioneer
 * [new ref]         07f7609270e7354f059c02d58fd55554f62d5e83 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 07f7609 Bugfix build release (rhbz#2174394)