Re: TW Firefox 151.0.4 - pushing World Cup Widget Ads to users??

I took a very quick look and saw that the preferences are written to the file 
~/.mozilla/<my default directory>/prefs.js (spotted that via a google search).

So I suppose if you kept a copy of that stashed safely away you could compare it 
to what it looks like later, realizing that it changes just from normal use. 
Meaning that just stopping FF and restarting it will change the file slightly.