The starting point for this project was the dissatisfaction with existing presentation slide applications. When the idea was born in 2009 there were only WYSIWYG editors for slides like PowerPoint or OpenOffice Impress or things like Latex Beamer.
The idea of this project was to define the content of your slide in a domain specific and descriptive format and transform it into the respective html format.
One goal was to not only support one of these html presentation systems but to be flexible about the desired framework. For every framework there was a XSLT transformation file that could be exchanged.
The whole process of the transformation was itself described by XML: There was a XProc XML pipeline that defines how the transformation should be done.