Hi
@Boyan M., thanks for posting today, I've merged you to this post with similar queries.
The offline file feature only allowed files to be accessed from within the Dropbox mobile app, and not via the file manager.
If this was possible via an Android device, then this was unintended, and the app has been since been updated as such.
As you're interested in this, you could post an idea
here for others to vote on, in order for the dev team to look into the option in future!