This package exists to house Ubuntu's settings for the Calamares installer.

If you want to add a new package for your flavor, here's how to do it:

1. Create a new top-level directory (like Lubuntu's, you could just copy theirs and customize).
2. Edit files and rename the branding directory for your flavor. All of the configuration files are pretty self-explanatory, but they're documented well upstream, so it shouldn't be hard to put your own spin on things.
3. Create a new binary package, and make sure to Provides+Conflicts against calamares-settings-ubuntu-flavor. This needs to be done because all subdirectories are installed in the same location, so this makes sure that nobody tries to install any two binary packages at the same time.

That's about it. If you have any questions, feel free to email Simon Quigley at tsimonq2@ubuntu.com or consult the upstream documentation.