Looking at the diff[1], this seems to remove Yandex-, Odnoklassniki-, and Mail.Ru-related bundled bookmarks and extensions (that apparently exist in some build configurations?), if this removes the search option as well it does not seem obvious.

(The editorialized submission title is obviously against HN guidelines, but it’s unclear what should be done about it if the original page title is purposefully obscure—and it does seem to be, even given what I said above. Wait for independent reporting to use a more straightforward one?..)

[1] https://hg.mozilla.org/integration/autoland/rev/a03a9c72d1db