I looked at the frequency of the appearance in the comments of phrases like “you have Russian letters crept into a reference” or “remove the Cyrillic alphabet from the link” and thought that such a number of people cannot have errors of this kind. Especially if it is usually Ctrl + C -> Ctrl + V from the address bar of the browser.
Accordingly, the conclusion suggests itself that the algorithm of the work of Habr himself makes substitutions instead of English letters for similar Cyrillic ones.
Well, naturally, one wonders why? ')
There is a suggestion that due to search greed. For example, when calculating Google PageRank pages take into account PageRank pages that refer to it, so Habr having a high PageRank does not want to share it with anyone, therefore replaces some letters with Cyrillic, so that links lead to non-existent places.
PS You can also add this assumption is popular about UFOs. :)