Would it be possible to add compat with https://mods.factorio.com/mod/space-exploration-extra-items to its new XL belt entities for the loader and other buildings when the mod items are detected? The XL belt entities it adds are a a between between space belts and deep space belts using T2/T3 materials.

It doesn't add any belts, as of the moment, at least not on the public ver.

Ah, my mistake, that's a planned addition. Perhaps in the future then (and no point adding the mod to the soon-server yet then either, the belts were the primary purpose, being able to interleave belts before deep space belts is valuable).