And how would that support your claim that this post is:

misinformation. No data is sent by default, you have to opt in.

The relevant parts from this code comment about the "offline" mode are:

Firefox Suggest suggestions are enabled by default.

The onboarding dialog is not shown.

Which correspond to the code I've already linked to.

      case "offline":
        enabled = true;
        defaults.setBoolPref("quicksuggest.shouldShowOnboardingDialog", false);
        defaults.setBoolPref("suggest.quicksuggest", true);
        defaults.setBoolPref("suggest.quicksuggest.sponsored", true);
        break;

The code you cited just says that users with locale "en-US" are enrolled in the "offline" mode.

Basically:

• locale = "en-US" => "offline" => opt-out
• locale != "en-US" => "opt-in" with all possible dark patterns to trick the user into accepting it: user has to click the small "Not now" text which does not look like a button on the top right corner to disable Suggest.

To summarize, the "offline" / "online" Suggest Scenario have absolutely nothing to do with the fact that Firefox sends data to Mozilla or not, it only defines if the Suggest feature is opt-in or opt-out. Is this naming extremely confusing? Absolutely! But at this point it's clear that Mozilla has done everything possible to mislead users about what their "suggestions" really are.

So please, stop spreading misinformation while claiming that people trying to bring awareness about this awful "feature" are the ones providing false information. A code comment is not proof, your completely wrong interpretation of it even less so. If you don't agree, please link to the relevant source code which would contradict the one I've linked to.