Many modern emulators need a BIOS-like ROM/flash image to even boot up; the situation is much less clear there, since these usually contain software and can accordingly be copyrighted.

Some emulators solve this by providing their own (re)implementation, but that’s not always easy.

And even when it’s “just” iOS: That is copyrighted too! So it’s the same problem – either there needs to be an iOS ABI-compatible OS, or it’s probably not possible to emulate any application legally, unfortunately.

You are correct on all points of course. My main point was that unlike projects that distribute those components there's really no grounds for Apple to DMCA down the emulator's GitHub repo itself.

Agreed, unless Apple wants to make some Oracle v. Google-like claim on that iOS or firmware reimplementation violating their copyright, or maybe the emulator being capable at circumventing their FairPlay DRM for apps…?

I really hope I’m wrong about this, but I feel like between this and iMessage, Apple might lean on DMCA before too long to protect their walled garden.

Just look at how hard Nintendo shut down any attempt at emulation.

That's exactly who I was thinking of. I'm really hoping for some precedent to be set here at some point – right now there's a large amount of FUD looming over many emulation projects.

And yet emulators of Nintendo platforms are widespread.