It changed, but not really that recently. https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions/Distribution_options/Sideloading_add-ons https

It changed, but not really that recently. https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions/Distribution_options/Sideloading_add-ons https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/Web... Note specifically the step where the addon must be signed before it can be installed in this fashion. "Developer edition" does not require you have Mozilla's permission to install addons.