Might consider something like:

• do an 'unzip' pass on the HTML that saves just the elements and their data-mw attributes on one hand (no other attribs or text content), and everything but the data-mw attributes on the other
• fetch the data-mw-less pass for viewing
• on edit request, fetch the data-mw-only version, iterate through, and apply data-mw attributes in the same place

If there's runtime modification of the DOM for showing/hiding, plugins etc that may make the 'rezipping' tricky. But it should work in theory. :D

See https://phabricator.wikimedia.org/T78676 .. This new ticket can be merged as a dupe of that one, I think. The only thing that has stopped us from going ahead with that is that all existing editing clients (VE, Flow, CX) would need to update their code to fetch data-mw separately.

I pressed submit hastily .. but I think once those clients are equipped to do this, that will unblock T78676.

Thanks @subbu. I'll keep this card since the motivation is different but resolving that bug looks like it should meet our requirements so added it as a blocking bug. Thanks!