Currently unidCoreCriteria handles the labels for both fuels and ores. Fuels use a strictly level-based set of criteria. This is unfriendly to modders (myself and Aury in particular do a lot of messing around with reactor fuels that doesn't entirely respect the core level bands) and imposes artificial constrictions on fuels and reactor systems.

For future-proofing and ease of modding, this should be changed to a tag-based system (eg; "FusionFuel" for helium fuels, "AntimatterFuel", and the existing "ZeroPoint" tag), replacing the level-based system entirely. This allows fuel to be made for reactors at arbitrary levels whilw preventing incorrect labels being given by the engine.

Finally, a Fusion Fuel label should be added, for uranium fuel rods and similar items, using something like a FusionFuel tag.