Now auto comments look like this:

<span class="autocomment">undo:0||427587027|194.158.78.188</span>

(https://www.wikidata.org/w/api.php?action=feedrecentchanges&target=User%3APutnik%2FWatchlist%2Fruwiki)

It should be possible to specify the language and get the text of auto comments in the appropriate language, as well as in the HTML pages.