This web app is used to help with code reviews. It's a PWA so can be used offline. To use CodeReview, select (or drag and drop) a git commit/diff onto this site. Then you'll be able to leave comments, selecting lines for each if you'd like. The comments use the Conventional Comment format. Once you're finished leaving comments, you can export the review, send it over to the other person, and they can select this file to view the comments and leave replies.
This is a 'serverless' site with no database, so everything is handled in the client and none of the file or comment data is sent to a server.
The reason for the app was to aid in code reviews where companies don't use GitHub/pull requests or similar products. All you need to use this is any git diff or commit, then can add some comments, export the review and send it to the other person so they can import it and respond.