For the usecase of that screenshot, I would just have used https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions/manifest.json/sidebar_action h

For the usecase of that screenshot, I would just have used https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions/manifest.json/sidebar_action https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/Web...