A full background fade is an aesthetic thing at best, and it would be disingenuous to fully fade a page if some parts are not in fact blocked (i.e. remain click

A full background fade is an aesthetic thing at best, and it would be disingenuous to fully fade a page if some parts are not in fact blocked (i.e. remain clickable). So I think it would require no changes, it would just look different. Having said that, I see no reason to support Like buttons OR modals and I would be fine with millions of sites being forced never to use them. We know Facebook Like buttons are over-engineered trackers whose domains are best blocked at your router. And when modals are not being abused for things users don’t want, the remaining “good” uses for modals would still be better implemented as less-intrusive and more-asynchronous things (display a modeless background message with buttons, for example).