Available as:
It is a page action so the icon (
) only shows up in the URL
bar when the page contains React-managed DOM. It is off by default -- you have to click the icon to highlight the elements rendered/managed by React (and you can click the icon again to toggle the highlight off). You can install this from the Chrome Web Store.
Credit for the original idea goes to someone on Twitter who tweeted a one liner. I can't remember who it was or find it so if someone knows, please let me know.
