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