This Scratch viewer is a free and handy utility that can be used to convert a Scratch file into HTML file, and you can easily view the contents of the file in your browser.
This app only works locally without going through the server. It allows you to view a file instantly, real-time. You can select Scratch files to view from your local computer and from Google Drive directly. Supports SB, SB2, SB3 file formats.

An SB2/3 file is a program created with Scratch, an application development platform created at the MIT. It contains Scratch programming language code used for creating stories, small games, and animations.