"The text is small, but we're working on translating. It appears that it's Mega Evolution remains Steel/Psychic, with Tough Claws. Although it is hard to make out, attack or speed seem to be the stat that has a significant increase in when mega evolving.Steven retains his title of champion."
Looking most likely that the ability is in fact Tough Claws.
Oh, that's good to hear! tbh, I'd rather it have the Speed boost than decrease for aforementioned reasons (i.e., faster Pokemon could launch super effective attacks against it). I hope its Special Attack doesn't get much of an increase, or doesn't increase at all. I always found it odd how some of the Megas experienced increases in an attacking stat that wouldn't've helped them much. (For example, Mega Charizard X gains +21 in its base Special Attack, despite it not being able to learn any of the Special moves that make contact.) I mean, I guess it might be to prevent the Pokemon from becoming too overpowered, but still.