> [...] the extension gets silently pushed to all the US users(!)
Non-US user here, my Firefox got it, too.
Non-US user here, my Firefox got it, too.
https://www.whatismybrowser.com/detect/what-http-headers-is-...
BTW: the extension we all talk about here has exactly this site that is used for checking the headers hardcoded inside, obviously in order for the developers to test their newly coded functionality with which they add an additional header entry in the request to some specific sites, specifically, the "main target" is a brand (I've given the link earlier on in this thread). It's obviously an advertisement for the US as that "main target" site is only meaningful to the US public. But it's obviously not the whole story.
If your language is not en-US it's worse than what I've understood.