What is the question? What do you want to achieve?

I want Firefox to never ever interrupt me with a request for rating when I am trying to use the browser. There is nothing that ruins any experience and goodwill in using anything than trying to do something and then be asked to rate the app.

So I will take an advanced developer option, about:config, or even a fork of the app, if it ensures I never get asked for an app rating again.

Does such an option exist in the current version of Firefox for Android?

I understand. I don't recall anything like that ever happening to me, but I use Nightly. However it may have other features that could annoy you, so the choice is yours.