$ git clone -n https://src.fedoraproject.org/rpms/libgnomeui.git /var/lib/mock/f42-build-3273911-41313/root/chroot_tmpdir/scmroot/libgnomeui
Cloning into '/var/lib/mock/f42-build-3273911-41313/root/chroot_tmpdir/scmroot/libgnomeui'...
$ git fetch origin f28c02b28fe2aaa5ffc495d339f66ae4cc954bfe:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/libgnomeui
 * [new ref]         f28c02b28fe2aaa5ffc495d339f66ae4cc954bfe -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at f28c02b fix FTBFS