Now Source Viewer is a free Chrome add-on developed by benhowdle89. It falls under the category of Browsers and is specifically listed as an Add-ons & Tools subcategory. This handy extension is designed to detect public Now sites and provide a convenient way to view their source code on Zeit.

With Now Source Viewer, you won't have to manually navigate to the source code page for every site you visit. This extension automatically sends a quick request to each site and checks if the "/_src" page exists. If it does, it adds a "View Now Source" button to the webpage, allowing you to easily browse the source code of the site.