Thanks for those links! From the code comments: "it won't cause any more bias than what the page_random scheme causes anyway. Trust me, I'm a mathematician. :)

Thanks for those links! From the code comments: "it won't cause any more bias than what the page_random scheme causes anyway. Trust me, I'm a mathematician. :)" Git blame says the author was "Ilmari Karonen" (https://commons.wikimedia.org/wiki/User:Ilmari_Karonen https://commons.wikimedia.org/wiki/User:Ilmari_Karonen), 15 years ago!