I have first modified a template using Google Slide. The file was originally created by PowerPoint. I modified the layout of the (only) master. It appears that PowerPoint can read these after exporting from GSlide, but python-pptx will read some default layouts, but cannot identify/read the modified ones.
To summup: GSlide Masters and Layouts are not read but a default master+layout is applied instead.
I have first modified a template using Google Slide. The file was originally created by PowerPoint. I modified the layout of the (only) master. It appears that PowerPoint can read these after exporting from GSlide, but python-pptx will read some default layouts, but cannot identify/read the modified ones. To summup: GSlide Masters and Layouts are not read but a default master+layout is applied instead.