YouTube Center are using a combination of ant (Java), python and executables to build YouTube Center.
The build system is made in ant and require ant and java to be installed.
ant all
-- Build everything below except for the styles.ant firefox
-- Build the Firefox addon (.xpi)ant firefox-legacy
-- Build the Firefox legacy addon (.xpi)ant chrome
-- Build the Chrome extension (.crx)ant maxthon
-- Build the Maxthon extension (.mxaddon)ant opera
-- Build the Opera extension (.oex)ant userscript
-- Build the userscript (.user.js)ant safari
-- Makes everything ready for Safari to finish building YouTube Center.ant styles
-- Rebuilds all the styles.