Text from every slide, in order
Each slide's text is read straight out of the .pptx file and written to its own PDF page, in slide order.
A .pptx is a zip of XML files, and the text lives in there as text, so it can be read directly without needing PowerPoint installed or a copy of Office on a server. Slide order is taken from the file's own numbering rather than guessed. What you get is a page per slide containing that slide's words.