It would be nice to have something like this except for Metal. I'm unsure why Apple made Metal an Objective-C API when C + Core Foundation would suffice. One big advantage of a C API is it's easy to interop with other programming languages.
For example, there was a time where Steve Jobs threatened to forbid iPhone apps not written in Obj-C, which would have destroyed the cross-platform ecosystem, at Apple's expense. Luckily, he was talked down from being that extreme.
You can’t definitively prove something was written in Objective-C or Swift, but you can often definitively prove something was not written in either pretty easily just by looking at the assembly.