That's Forge's OreDictionary. And I'd really like it if people stopped pretending like Tekkit adds things. Refer to the metal by the mod that adds it, not if it was in "classic" or "lite"
It's not pretending, it's an actual fact that Tekkit does add things to minecraft, that's generally the point of content pack mods for minecraft. Saying that Tekkit (or really honestly any other mod pack) doesn't add anything to the game is like saying you don't breathe air. You can say it, but it's not true, and if you believe it, pretty much everybody else will disagree because it's literally just not true. And if you're saying that we should only refer to the metals by mods, then no. For one, we can't be assed to actually go and be like "Oh well the blah blah blah tin is now compatible with the bleh bleh bleh tin." No we really won't because there's no point, and it's much easier for us to say "Classic" or "Lite" rather than actually look up where each Tin came from.