[css-fonts] Reduce layout shift via @font-face descriptor(s) overriding inline spacing #5533
Description
In #4792, we agreed to add @font-face descriptors to override ascent, descent and line gap of a font, which allows us to match the line height metrics between fallback and primary font, and hence, reduce layout shift.
In #4792 (comment) I also proposed advance-override to override the inline spacing and further reduce layout shift. The proposal still has several problems and hence remains under discussion.
So I opened this issue to specifically discuss if we should add new descriptor(s) to @font-face to override the inline spacing for matching text widths and reducing layout shift; And if we should, how should the new descriptor(s) work.