Cobra is open source and is made available free of charge. Its source code is released under the LGPL license. Note that Cobra uses the Rhino 1.6R5 Javascript engine, which is released by the Mozilla Foundation under a dual MPL/GPL license. Given that the GPL license of Rhino is the one that is compatible with Cobra's license, it is our opinion that users must observe Rhino's GPL license when linking Cobra. 