I use it in Firefox on the computer and only occasionally use Google. I raised a bug with Apple to request the ability to set it on mobile Safari. At the moment

I use it in Firefox on the computer and only occasionally use Google. I raised a bug with Apple to request the ability to set it on mobile Safari. At the moment you can only use Google or Bing (or Yahoo-Bing) File duplicates if you want it as Apple counts dupes as up votes.