Some packs like UNU and Trin would like to have new special fuel types for our engines (hydrogen, electric, nuclear…) but it might overload the config and require a core mod update if ever we want to modify those fuel systems at the moment, that’s why it would be great to automatically update the MTS fuel config by adding a MTS pack (maybe by some kind of jsons?)

But, you can already add different fuels. Once you add them they'll be available in the config for modifying. Seeing as how I still have yet to get any response on the issue of other liquids for other default fuels, I'm hesitant to mess with fuel even further.

You got pinged on discord with a list of potential redstone related liquids, but it so hard to find, it’s said nowhere

Implemented in V15.7.0. Use fuelType of "redstone".