Now that there is a Godot BaseApp available on Flathub, we should write a tutorial to package a Godot project as a Flatpak. It should strive to be as short as possible and cover only the essentials, such as:

• Creating the required .desktop and AppStream metadata files. We can add templates to the documentation page itself.
• Creating a Flatpak manifest (based on a template) and editing it to suit the project.
• Setting up sandbox permissions depending on the project's needs.

For more advanced use cases, it should link to the Flatpak documentation.