SUPER SMASH BROS. FEUD - BIG update in latest post.

[iyenal]

-I noticed Ultimate runs on Unreal Engine. Which means its guts might be ripped and datamined for me to look at if / when the files become available for modding. So up until then, I will work on content that does NOT entail desired stuff new to Ultimate.

Check this: https://www.reddit.com/r/smashbros/comme...al_engine/ remember that it's just a rumor nothing really technical.
And personally, I doubt also that Nintendo internal development teams uses a thrid-party engine.