The spoof English prompt is not always seen by users
While working on #12967 (moved), Kathy and I noticed that the spoof English prompt (the one that includes "Would you like to request English language web pages for better privacy?") is only shown when a new tab is created. But some users may never create a new tab, which means they will never see this prompt.
We should display this prompt as soon as the first (default) browser window is ready.