Here you can find the official SEO related guidelines of Yandex
Search optimization Guide
Yandex announced on their Russian blog that they have launched a new algorithm aimed at improving how they handle long-tail queries.
Long-tail queries are several words entered into the search box, more often seen in voice queries these days. Yandex says about 100 million queries per day fall under the “long-tail” classification within their search engine.
The Palekh algorithm allows Yandex to understand the meaning behind every query, and not just look for similar words. Which reminds me of Google RankBrain.