$ git clone -n https://src.fedoraproject.org/rpms/lilypond-doc.git /var/lib/mock/f42-build-side-1-3501328-45974/root/chroot_tmpdir/scmroot/lilypond-doc
Cloning into '/var/lib/mock/f42-build-side-1-3501328-45974/root/chroot_tmpdir/scmroot/lilypond-doc'...
$ git fetch origin 7dc2f19516674224864cb00e874d5cbc878cc6ea:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/lilypond-doc
 * [new ref]         7dc2f19516674224864cb00e874d5cbc878cc6ea -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 7dc2f19 2.25.25