$ git clone -n https://src.fedoraproject.org/rpms/gnulib.git /var/lib/mock/f40-build-799026-142136/root/chroot_tmpdir/scmroot/gnulib
Cloning into '/var/lib/mock/f40-build-799026-142136/root/chroot_tmpdir/scmroot/gnulib'...
$ git fetch origin 68b1d5348cb51a9b1a642af6c821f406d3878f7a:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/gnulib
 * [new ref]         68b1d5348cb51a9b1a642af6c821f406d3878f7a -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 68b1d53 Bumped release