Are all the ext code free to anyone to use ?
Unless you need a commercial license, yes it's free. Please spend some time reading the home page and the licensing information. If you have further questions regarding licensing, email email@example.com
it's LGPL license which mean u can use it even in commercial product without paying
if u changed the ext code,u release the changed code under LGPL or pay a commercial fee,if u want professional support,u can pay for it