edit-diagram.html does the I/O with GitHub and uses draw.io in embed mode for diagram editing. The page supports the following URL parameters: user, pass, repo, path, ref and action=open (the Edit link above is an example). Using action=open, links for immediate diagram editing in GitHub can be created (requires user and pass parameters). You can also use files on GitHub as templates in draw.io via the url parameter (see Edit As New above).
Supported file formats: .png, .svg, .html and .xml (default)
self-editing.svg is an SVG file with embedded PNG data (as a workaround for missing foreignObject support in Internet Explorer). This combines an image format (eg. for <img src="...") with scripting for GitHub integration. (Click on the link, not the image to enable editing.)
self-editing.html is a HTML file with embedded PNG diagrams. The file uses nanocms.js for GitHub I/O and diagram editing. The page and the diagrams can be edited.