At the moment, this repository functions as a public issue tracker for known issues, and at a later date can be used to modify the game panel's frontend completely (though to be decided later on). How to run this locally, etc. isn't something we currently will provide support for, and this should be treated purely as a reference for CSS modifications for now.
The locale strings can be found inside of src/locales/* but any new language should not be pull requested directly and should be done through our localization platform instead. You can find more info in our Discord.