This is a very short answer, which I couldn't find an answer to, not in in the docs and not anywhere over the Internet:
On Android, apps can offer the user to choose files from them, to be chosen from other apps. For example, the Google Photos app allows to choose photos files from it. This is done by implementing DocumentProvider .
I'd like to ask if it's possible to offer my app's content, only to my app itself.
This can help in the case of providing photos selection, for example, that is relevant only for the app itself.