The Web Viewer plugin displays web and document formats in a viewer window: HTML and MHT pages, XML, Markdown (.md, .mdown, .markdown), SVG, and PNG images. Markdown files are rendered with GitHub-style formatting, including their images.
The plugin uses Microsoft Edge WebView2, which is part of Windows 10 and Windows 11. On older systems, install the Microsoft Edge WebView2 Runtime.
From Sally 1.0.37, if WebView2 cannot navigate to or display a file, the viewer shows an error page with the failure details. If an SVG fails to open, include that message and the file when reporting the problem.
From Sally 1.0.38, a failure to initialize WebView2 also shows a readable message, including the initialization stage, error code and file path or URL. Include these details and the original file when reporting a problem.
See the File Viewer section in Using Plugins for a description of basic work with plugin viewers.