The question what video is this from usually arrives with a short snippet: a few seconds forwarded in a chat, a clip reposted without credit, a scene you half-remember. You cannot search it by name because you do not know the name — but the frames know.
Upload the snippet and the tool samples frames across its length, then looks for the webpages containing the same imagery. Those pages — often the original video page, a repost, or an article using the footage — carry the titles, descriptions and context that answer what video is this from in practice.
The tool above takes an MP4 or WebM file up to 100 MB and 10 minutes. No account needed. The rest of this page explains how the matching works and how to read the results so the answer is grounded, not guessed.