For my art history class, my teacher gave me a large PP with a slide for each artwork we needed to learn, so that I could use upload the images plus the artwork identifications and classifications to Memrise for virtual study cards.
I grew tired of copying the two lines from each slide, so I decided to try to parse the PP in python to export a list of artwork IDs and classifications. For example, here 
El Greco: Mannerism.
I found out that a .ppx file is really just a .zip, so once I extracted the PP it was easy to find the slide files, which were all .xml.