$ git clone -n https://src.fedoraproject.org/rpms/makedumpfile.git /var/lib/mock/f42-build-3273302-41310/root/chroot_tmpdir/scmroot/makedumpfile
Cloning into '/var/lib/mock/f42-build-3273302-41310/root/chroot_tmpdir/scmroot/makedumpfile'...
$ git fetch origin d6816571ee82c1e1d75604e963bc810b59d814f4:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/makedumpfile
 * [new ref]         d6816571ee82c1e1d75604e963bc810b59d814f4 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at d681657 Allow all users with commit access to the repo to create a build