It's not an uncommon terminology in the WSI portion of graphics APIs, I was just pointing out that it doesn't actually mean anything to the hardware/lower stack. There are only buffers.
(There can be restrictions on which buffer formats and layouts can be used for certain things, scanout being particularly picky, but a regular window can be textured from pretty much any buffer.)
https://developer.apple.com/documentation/Metal/customizing-...
The buffers are not that different, it really just means “extra allocation”