I believe the extension you are looking for to outline the React components on the page is https://chrome.google.com/webstore/detail/react-developer-tools/fmkadmapgofadopljbjfkapdkoienihi?hl=en.
Ah, I see. The Components tab shows up (with this extension) if React is detected, but if not then I won’t see this option. Thanks Tristan!