This clipper can capture, at your request, the complete content of the page you are viewing, including text, images and text formatting (HTML tags). It can also capture, at your request, the selected text or take a screenshot of the part of the page you would have selected.
This data is then sent to your locally running Joplin application. The Joplin application will only get your data if you enable the Clipper service in the application (which is disabled by default).
The Joplin applications, including the Android, iOS, Windows, macOS and Linux applications, do not send any data to any service without your authorisation. Any data that Joplin saves via the clipper, such as notes or images, are saved to your own device and you are free to delete this data at any time.