It would likely still be listed as mana in the prompt, and even if it were re-coded to list differently, and any relevant help files were altered to match the change, it would still function as the same basic thing in the mechanics of the game design.

So, just like I do with my non-spellcasters, if it seems odd to be using something that in the real world you'd think of as 'magical energy', just figure it's part of how this other world you're immersed in works. We can't do tells in the real world either, but we can suspend disbelief about how Thera works. :)