Coming to Chrome 65: Local Overrides. Make a tweak and DevTools saves the changed file to a location of your choosing. On next load, DevTools loads the local file rather than going to the network. https://developers.google.com/web/updates/2018/01/devtools#overrides …pic.twitter.com/tQc0DrQsnW
If you edit the HTML that came over the network (via the Sources panel), it should. HTML edits in the DOM Tree (on the Elements panel) don't work.