For e10s compatible FontFinder try https://addons.mozilla.org/en-US/firefox/addon/font-inspect/ FontFinder has 4 key pieces of functionality: Any font on a page can be completely analyzedAny piece of an element's information can be copied to the clipboardFont-families can be disabled from the entire page, to test degradation for cross-OS supportAny active element can have any piece of the font's o