The extension did not do anything unless you put in a secret setting. It wasn't promoting anything.
replyIf this had been a hardcoded easter egg there would have been no real complaints. But showing up as a mystery extension spooked some people, and then misreporting made it spread a lot further than if all the reporting was accurate.
I just rewatched Mr Robot and that actually sounds cool. What was the secret setting ?
replyOnce you get the extension installed, you open up about:config and add a boolean preference "extensions.pug.lookingglass" set to true.
replyThere might have been another way to do it later but we'll never know.