What is it?
Yandex DataLens is a business analytics service It lets you connect to various data sources, visualize data, create dashboards, and share the results. With Yandex DataLens, you can track your product and business metrics directly from data sources to make data-based decisions.
Documentation available here:
https://cloud.yandex.com/en/docs/datalens/
This pretends to be a source code which was leaked earlier, not what they open sourced.