Haha you are right. Very bad explanation on my side.
So the “app” in question is a vcds-mobile car diagnostic device. It works with the phone hotspot and shows car data live, all in the browser. It saves reports and I can read them from within the browser. so either the device itself has some memory and that is where they are saved but I doubt it or it DOES save them in some browser cache somewhere which seems more likely.
On the other hand I did a search for some of these logs and did not find them so I don’t know in the end.
Thank you anyway for the kind CL tips.