Comment by OkCompute64

I set the following in my user.js to disable this kind of thing. It keeps my default search engine suggestions but disables all the junk. Strictly speaking I think the last line is technically redundant as quicksuggest.all=false should disable .sponsored as well but no harm in being explicit about it.

  user_pref("browser.urlbar.suggest.engines", false);
  user_pref("browser.urlbar.suggest.openpage", false);
  user_pref("browser.urlbar.suggest.topsites", false);
  user_pref("browser.urlbar.suggest.quickactions", false);
  user_pref("browser.urlbar.suggest.recentsearches", false);
  user_pref("browser.urlbar.suggest.quicksuggest.all", false);
  user_pref("browser.urlbar.suggest.quicksuggest.sponsored", false);