Why is Observation published as a Framework?

Observation was proposed in swift-evolution and I thought it was added as a Swift language feature, but Apple's documentation describes it as a Framework and I am confused.

Isn't Observation a Swift language feature? Is it possible to use it on non-Apple platforms such as Ubuntu?

Correct, it is perfectly usable on non-Apple platforms. I don't know if I'd call it a "language feature"; it's a core library/part of the standard library.

Apple's docs use the word "framework" basically as a synonym for "(dynamic) library". It's just the word they use. Even the Swift standard library is described as a "framework":

As are their JS libraries


I was puzzled by the word "framework", but now I know that I don't have to be confined to it. Thank you!