Yeah, that specific case wasn't fixed; it appears that Mozilla doesn't intend to let addons run on `about:`. However, they did make `about:` respect DNT by disabling GA.
WebExtensions currently fall short when it comes to any addon that modifies the UI significantly (tree-style tabs etc), though it's been mentioned in some other comments here that they're talking to addon devs to extend the API where possible.
WebExtensions currently fall short when it comes to any addon that modifies the UI significantly (tree-style tabs etc), though it's been mentioned in some other comments here that they're talking to addon devs to extend the API where possible.