I have not found much publicly-available Halo data-format documentation; the most I've found is the map-file header and tag-catalog formats.
Would anyone be able to provide any more?
I'm hoping to start an effort to reverse-engineer the remaining Halo-map data formats.
And might it be possible to make available the source code of whatever utilities you people have written, like Halo Map Tools and SparkEdit? That would be very helpful for other mod-tool writers.