New pages

If I understood correctly the description of the wgArticleFeedbackLotteryOdds configuration variable (whose value for enwiki, according to InitialiseSettings.php is 2.7), and the JavaScript code where its value is used, the list of "random" articles where the extension is enabled is not "fixed".

In fact, every time a new page is created, MediaWiki associates a unique number to it (the page_id, whose value is preserved across edits and renames, but not deletion and recreation). This number is what the ArticleFeedback extension uses to determine if a page should be rateable or not:

If the last three digits of the page_id of an article is in the range 000, 001, ..., 026 (=trunc(10*wgArticleFeedbackLotteryOdds)), the page is added to the list;
If the digits are 027, 028, ..., or 099, then the page is not added.

So, from time to time, 27 new pages are added to the list, and the next 973 are skipped. E.g.: the page "Blue Wave (disambiguation)" mentioned above is rateable because the last part of its page_id (31813011) is less than 27, as also happens with a redirect page having page_id equals to 31813024. Nonetheless, a page which has page_id=31813027 is not rateable.

Helder‎

Helder, that's correct, the lottery mechanisms is how the article sampling has been implemented. CambridgeBayWeather – sorry I misunderstood your question, which I thought referred to why AFT is being enabled on pages that are potential candidates for deletion. Incidentally (as I noted in reply to another comment) AFT can still be enabled on individual pages via Category:Article Feedback Pilot.