Great question — answering as the UphillTech team:
For just a short look, rename it to .zip , create a temporary folder and unzip it there. The file preview.jpg will contain the rendered first page of the document in 72dpi. If you are interested in the text, you can try to filter Index/Document.iwa for readable text.
Full answer by jvb: https://superuser.stackexchange.com/a/1404400 (CC BY-SA 4.0).
Need it done for your business? UphillTech.