Unfortunate they didn't just copy over FF's sidebar api. https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions/user_interface/Sidebars https:/

Unfortunate they didn't just copy over FF's sidebar api. https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions/user_interface/Sidebars https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/Web...