From the warning before installing in FireFox: Add SingleFile? This extension will have permission to: - Access your data for all websites - In

From the warning before installing in FireFox: Add SingleFile? This extension will have permission to: - Access your data for all websites - Input data to the clipboard - Extend developer tools to access your data in open tabs - Download files and read and modify the browser's download history - Access browser tabs ... all of which I don't mind, as long as the extension can't exfiltrate any of the data it can access (send it to a third party). i.e. - no network connections from the extension - no modifying web pages or executing any code in the context of a web page Does anyone know whether these sorts of extensions can exfiltrate data? -- this is a concern if the project author's credentials are stolen by a threat actor, which has happened before.