RE: [css3-images][css3-background] Specify "CSS View Box" in B&B

[Tab Atkins:]
> I'm fine with a different name, if we can agree on one.  "CSS View Box"
> was the best that Elika and I could come up with.  It's kinda a viewport,
> in that it's the box that images render into, but not quite a viewport,
> because it doesn't automatically clip the image to its boundaries (whether
> or not to clip is a higher-level decision).

I got that. But given that viewBox is also an SVG element it could be
confusing; unless, maybe, it can be argued that they're very similar/equivalent
but I don't know enough about both to assert that's the case.