Amaya

The World Wide Web Consortium's browser/editor of record. Includes support for HTML 4.01, XHTML 1.0, XHTML Basic, XHTML 1.1, HTTP 1.1, MathML 2.0, many CSS 2 features and SVG. Includes Annotea, an annotation application based on XPointer and RDF. Instructions on compiling and installing the package on Mac OS X.