Very early preliminary update available here, in the same folder as above (in case the direct link is broken when I update/replace that file).
Basic belt brush functionality is technically working, in that you can use the usual hotkeys to increase belt brush size, and build them en masse using items from the inventory (despite a lua api warning that appears in the chat, which I haven't been able to pin down). Belt reverser was also working, though the keybind overlaps with the red cable hotkey.
It might not do curves properly, can't be placed on top of existing belt facing the wrong way, belt highlight wasn't working at all, with no idea how to fix, so I just disabled that script, and I haven't tested most of the other belt brush functions, so may have to come back to fix things later. That mod might be a little bit outside of my realm of experience to fix, with many moving parts in the scripts, and directionality that I don't quite understand.