In order to prievatly run the code, you will have to download the entire reposeitory. This will give you acces to the moder tool chain, Lit, used for this site.
After entering a text editor, the files you need to understand the page are: assets/DiplomacyExtensions1.css, index.html, src/DiplomacyHelper.ts, src/DiplomacyWebsite.ts.
npm run startnpm run build