In the XML PowerPoint format (.pptx), it's a line break (inserts an <a:br> element between the two lines). There's no vertical tab character saved out to disk

In the XML PowerPoint format (.pptx), it's a line break (inserts an <a:br> element between the two lines). There's no vertical tab character saved out to disk (who knows what PowerPoint does internally, though). I don't have the time or the initiative to figure out what the old .ppt format does here.