What software is Chordie using?

As far as I remember, Chordie once had a list of the open source software that was used for the document generation and visualisation og tabs. Now I can't find it.

As I would like to use the same techniques for my own private music sheets, I need the information:

What software is used to
1) transform from ChordPro to HTML?
2) compile the book in PDF-format.

Thank you for any answer!

And Chordie - this is the best site for guitar players! Thank you for providing it !

Best regards
Torben