1.4.0-Update
When flattool is first ran, that text has been made more understandable, as well offering to install flathub if that isn't found on the system.
Added a new command add-flathub which can add flathub to the user or system install.
Added a new command data-dir which will print the path of the supplied app query and optionally allow you to open it with the -o flag at the end.