$ git clone -n https://src.fedoraproject.org/rpms/kf6-kimageformats.git /var/lib/mock/f42-build-868902-176328/root/chroot_tmpdir/scmroot/kf6-kimageformats
Cloning into '/var/lib/mock/f42-build-868902-176328/root/chroot_tmpdir/scmroot/kf6-kimageformats'...
$ git fetch origin 420bf226d6df7a9dae57477b3a7a0efd522c7bc9:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/kf6-kimageformats
 * [new ref]         420bf226d6df7a9dae57477b3a7a0efd522c7bc9 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 420bf22 Rebuild for jpegxl (libjxl) 0.11.1