Spark uses proprietary JxBrowser component for cobrowsing/sparkmeet. They ask to add a disclaimer to the readme file:
Spark uses JxBrowser http://www.teamdev.com/jxbrowser, which is a proprietary software, owned by TeamDev Ltd. The use of JxBrowser is governed by JxBrowser Product Licence Agreement http://www.teamdev.com/jxbrowser-licence-agreement. You may not use JxBrowser separately from the Spark project without explicit permission of TeamDev Ltd.
It was decided not to go with JxBrowser, so disclaimer has been removed from Readme.