Well, curiously, X11 has no compositor, no definition of clipboard, and a drawing API that no one uses. It seems to me that precisely it is not trying to do any of these things, but rather providing the mechanism by which some other process (or processes) can do these things.
E.g. if tomorrow I want to implement a toolkit that wants to have 3 clipboards, I can; even without changing the server or the compositor process.
Well, curiously, X11 has no compositor, no definition of clipboard, and a drawing API that no one uses. It seems to me that precisely it is not trying to do any of these things, but rather providing the mechanism by which some other process (or processes) can do these things.
E.g. if tomorrow I want to implement a toolkit that wants to have 3 clipboards, I can; even without changing the server or the compositor process.