This is so incredibly infuriating but I'll attempt to not cuss too much.

Basically if you don't follow the situation the organization that published both Undertale and Deltarune soundtracks, "Materia Music Publishing", recently have been going after Undertale Yellow's soundtrack for copyright reasons. And honestly, they're not just a clown. No, they're the entire circus.

They're not happy with them using a remix soundtrack. In a free, non-monetized fangame. As well as the logo.

Brother in Christ.

What's a fangame?

A fangame is when a very passionate fan decides to make a fan project based on something that's logically not made by him, because to make a fangame of something you need to be just a fan and not the owner of the thing.

The concept itself implies that you don't legally own the thing you're working with.

They're saying that before making the thing, the UY team had to ask for Toby's approval and pay them for a license. What are they talking about? That's not something that happens in real life. No fangame creator would ever want to go through that process. If that'd be the case, there would simply be no fangames altogether.
Funnily enough though, 7 years ago UY Team actually DID ask for Toby's permission, and got it. And they still have a bone to pick with them. Just wow.

That's just an incredibly goofy duck-up. Honestly that changes nothing. I'm still planning to make Undertale remixes for Swapfell because that's what fangames always did, do and will do. Not even just Undertale. Look at Lisa, look at Omori, look at OFF.

Honestly just disgraceful. If I were them I'd publicly apologize for that.