GitHub Markup
Determines which markup library to use to render a content file
...The HTML is sanitized, aggressively removing things that could harm you and your kin—such as script tags, inline-styles, and class or id attributes. Syntax highlighting is performed on code blocks. See github/linguist for more information about syntax highlighting. The HTML is passed through other filters that add special sauce, such as emoji, task lists, named anchors, CDN caching for images, and autolinking. The resulting HTML is rendered on GitHub.com. The dependencies listed are required if you wish to run the library. ...