Hi, Thanks for sharing this info. I also didn't know about this function. It's actually a little hidden. They should make this more obvious if you ask me.
One other question i have is, when you have let's say an excel file in the files app on your iPad (does not have to be onedrive). Then i don't need to slect open with, instead when i tap the excel file, it already knows it has to open the excel app. So this means the iPad linked the the .xlsx files to the excel app. It would be nice if the Adobe pdf app would do the same for .pdf extension. Or am i missing something?