I have the related setting in about:preferences disabled, but I see a couple of suggestions by "Firefox Suggest" in my private browser window, which is a bit surprising.

Is this the intended behaviour?

This is due to the confusing state of Search preferences (for which we have a proposal but it requires coordination with UX) and the confusing Firefox Suggest name (for which I spent enough words, I think).
That pref only refers to Search Suggestions as in suggestions coming from a search engine, I can totally see how it can be misinterpreted.
So it doesn't apply to anything else that is not coming from a search engine.

Whether Firefox suggest should or not respect PB differently, that's up for debate. Drew, was there any discussion related to Suggest in PB windows?

(In reply to Marco Bonardo [:mak] from comment #1)

This is due to the confusing state of Search preferences (for which we have a proposal but it requires coordination with UX) and the confusing Firefox Suggest name (for which I spent enough words, I think).
That pref only refers to Search Suggestions as in suggestions coming from a search engine, I can totally see how it can be misinterpreted.
So it doesn't apply to anything else that is not coming from a search engine.

Oh, I see. Thank you for clarifying. Yeah, that felt a bit confusing, especially given that I expected to find a setting to disable the Firefox Suggest behaviour :)

that's under the Privacy section... yes this split is another confusing layout in preferences, we're aware of it.

We label all your history and bookmarks as "Firefox Suggest", which is pretty confusing. When you type something in the urlbar in a private window, of course Firefox will find all your matching history and bookmarks, and they will be shown under the "Firefox Suggest" label.

The actual Firefox Suggest (TM) feature that fetches sponsored and non-sponsored suggestions is disabled in private windows. These suggestions have a ? help button in them, which is an easy way to identify them. Sponsored suggestions also have a "Sponsored" label inside them. If you do not see the ? button in any suggestion in a private window, then the feature is working correctly.

It looks like you're using a non-en-US locale though, and in that case actual Firefox Suggest suggestions aren't enabled at all, so you won't see them even in non-private windows.

(In reply to Drew Willcoxon :adw from comment #4)

We label all your history and bookmarks as "Firefox Suggest", which is pretty confusing. When you type something in the urlbar in a private window, of course Firefox will find all your matching history and bookmarks, and they will be shown under the "Firefox Suggest" label.

Yeah, that's what's happening then. It's fetching from my local history!

The actual Firefox Suggest (TM) feature that fetches sponsored and non-sponsored suggestions is disabled in private windows. These suggestions have a ? help button in them, which is an easy way to identify them. Sponsored suggestions also have a "Sponsored" label inside them. If you do not see the ? button in any suggestion in a private window, then the feature is working correctly.

It looks like you're using a non-en-US locale though, and in that case actual Firefox Suggest suggestions aren't enabled at all, so you won't see them even in non-private windows.

Thanks for your explanation, the feature appears to be working correctly then, although in a slightly confusing way due to names! Happy to close this bug as INVALID :)