Matplotlib (MPL) is python charting library, with function similar to Gnuplot and interface/API modelled on Matlab.
AsciiDoc is converter from ascii text files (with very human readable markup) to html and other doc formats.
The MPLW is MPL wrapper, which can work as AsciiDoc filter. This means that AsciiDoc document can have snippets of MPL commands to generate charts.
Full documentation at http://volnitsky.com/project/mplw