Use of drawWindow method from CanvasRenderingContext2D is deprecated. Use tabs.captureTab extensions API instead https://developer.mozilla.org/docs/Mozilla/Add-ons/WebExtensions/API/tabs/captureTab
Le uso del methodo drawWindow ex CanvasRenderingContext2D es obsolete. Usa in vice le API pro le extensiones tabs.captureTab https://developer.mozilla.org/docs/Mozilla/Add-ons/WebExtensions/API/tabs/captureTab