Help build application dependencies. More information: https://docs.flatpak.org/en/latest/flatpak-builder-command-reference.html.
flatpak-builder path/to/build_directory path/to/manifest
flatpak-builder --repo=repository_name path/to/build_directory path/to/manifest
flatpak-builder --install path/to/build_directory path/to/manifest
flatpak-builder --gpg-sign=key_id --repo=repository_name path/to/manifest
flatpak-builder --run path/to/build_directory path/to/manifest sh