DOMRec doesn't handle dynamic changes to rules in CSS stylesheets because our app doesn't do that. If we needed to do that, I'd try wrapping the CSSOM API proto

DOMRec doesn't handle dynamic changes to rules in CSS stylesheets because our app doesn't do that. If we needed to do that, I'd try wrapping the CSSOM API prototypes. (Of course DOMRec does handle changes to 'style' attributes on DOM nodes, because those do generate mutation notifications.) Similarly, DOMRec doesn't handle cross-origin frames, because our app doesn't use them. To make that work I guess we'd have to port to a browser extension and even so it would make things quite a lot harder.