How does apps be able to download while they don't have access to files on the phone?

I was looking for some new apps on F-droid and i saw an app called QuranApp which can download files while it doesn’t have any access to file like reading files permission and modify or delete the content of shared storage permission, So could anyone explain this to me??

Apps can write to folders like Downloads without needing storage permissions. They can also read the files that they created, but not any other files.