Yep, you could theoretically do a similar sleeper malware as extension for Firefox based browsers.

But that is not what this article is about.

No where in this article is anything about a Firefox based browser mentioned.

So, again, go back your original comment on my comment.

You tried to put a bunch of words in my mouth, now you're trying to argue hypotheticals based on conjecture.

Are you trying to make some kind of point?

Or just waste the time of anyone bothering to read this?