Would it be possible to have a list of loaders/beltboxes that your mod added that other mods would be able to access? It would make my collision mask adjustment a lot more future proof, in case some new integration adds new tiers.

Either with the type, or a seperate list for each type.

The names dynamically generate based on the associated belt tiers, so they should be predictable based on that, but unfortunately they're not very distinctive; <beltname>-loader and <beltname>-beltbox. The loaders also have a bit of magic added to the order string, if it's easier to detect on that?

Some belts don't follow the naming conventions (like factorio extended plus), which makes it a bit more difficult.

Looking at your mod some more, I found that it uses the order field for Metadata, which is basically what I originally wanted.