For agents, on top of README.md, which they read first.

• Never keep download_url or git_url. GitHub's download_url for a private repository carries a temporary access token. Raw reads download_url only to tell a submodule from a file, and a test holds that nothing parsed contains it.
• Raw HTML in markdown stays text. The pages render the repository's markdown on this site's origin.
• ?raw never serves HTML as HTML. media_type returns plain text for every text file but SVG, and the Worker adds content-security-policy: sandbox.