[css-backgrounds] border-position

Hello,

Has a `border-position` property (or similar) ever been considered? I
couldn't find any discussion about it so, please let me know if I'm missing
something!

Plausible use cases out of my head:

1. Centering the border. With tools like Illustrator and Sketch displaying
the border by default at the center (presumably for SVG), it's often
necessary to redraw/resize/realign the layers aimed at being implemented in
CSS in order to account for the different border positioning method.
Additionally, some border effects are simply not possible today in CSS
because of the lack of proper centering (as in, border + outline isn't a
reasonable hack).

2. While `box-sizing` can emulate a potential `border-position: inside`,
the mental model of these properties are radically different, and I tend to
think designers would find the latter much more natural.

Thanks,
Ben