Parses a subset of LaTeX into an AST and converts it into XML or any of a number of output formats (EPUB, MathML, etc.).
To be honest, I am a bit disappointed that it is necessary to use a separate tool to do this in the first place.
Say you want to write a book and publish it in both printed and ebook form and ideally also have a customizable, stylable web version of it with good navigation and accessibility, what format are you supposed to write it in if not LaTeX? DocBook? AsciiDoc? Scribble?