So before the release of XY Fennekin was shown to learn the move Glow Punch, but it seems it's not in the final game. Did Game Freak remove it, did it get renamed, just what became of it?
Actually I spent a little time looking through and here's what I think;
If you dig through Fennekin's learnset on the basis that Glow Punch was renamed or something, the only move that is remotely punchy is Power-up-Punch. So what I think after looking at their animations and stuff is that
Glow Punch is in fact Power-Up-Punch.
If you look at around 0:49 on this video (it's really blurry) of Power-up-punch and this one of the so called 'glow punch'from about 0:16 you can see that the animations are basically the same.
Additionally, Fennekin learns Power-Up-Punch and it is super effective on Litleo, which is an normal-fire type (Apparently there was a super effective sound when the move hit on Litleo).
Game freak probably cut it off and replaced it with mystical fire,