Background service_worker that can access the copypasteBackground.js page. This script does not have access to the web page. It listens for posted messages from the content script to perform to get and set value to public variable. Host integration extension code which exchanges messages to/from content script based on integration with native application message exchange with .net host application. Message flow: browser window.dispatchevent -> (content script)MessageAaptor.sendMessage-> (extension)MessageConnector.connectsendNativeMessage-> (content script)MessageAdaptor.onMessage.addListener Receives message from content script which manages native application message exchange to hostName application. Host name must be registered in windows registry!