I'd like to get the spec compliance bugs fixed in ext-dom for PHP 8.4. Normally that wouldn't be possible as the BC break would be too huge. However, we now have new classes in the DOM namespace as a result of the HTML5 RFC.
I'd like to propose to switch to a "spec-compliant mode" when one of those new DOM\HTMLDocument or DOM\XMLDocument classes are used.
This way, existing code will keep on functioning while new code can enjoy spec compiance.