[p1necone]

MacOS always renders at an integer multiple of their internal "logical" resolution, and then just shrinks the framebuffer down at the end to whatever the native resolution of the target monitor is.

Fractional scaling is rendering directly to a framebuffer at the target monitors native resolution, and scaling your UI fractionally to look right on the target screen size.

Apples approach is more resource intensive, but probably makes UI layout implementation a lot simpler and more consistent + potentially looks better than rendering at "real" native res for a lot of content.