The addon itself doesn't (and can't) rewrite any request, it only tells the browser to upgrade all http resources before blocking them. In other words, It can only apply to the top-level request rather than a specific request.

Simply adding this will break many things inevitably. I originally wrote this addon only to experiment the idea and it happened to work for me. I agree that it can be further improved such as the UI and shortcuts, but I just don't have the interest to work on it. This addon is licensed under GPL, so please feel free to make any changes and create a PR on GitHub.