Hotwire/Turbo primitive that scopes a region of a page so it can be loaded lazily and navigate independently of the rest of the page. In Yaroslav Shmarov's talk, Turbo Frames power async index loading (each record in its own frame with a show URL), modals overlaying content without full page refreshes, YouTube-like independently-updating regions, and turbo-action=advance to update the URL while re-rendering only the frame's content.