This plugin adds Yandex Metrika pixel to your website to track your users' behaviour such as clicks, scrolls, page visits, etc. It doesn't collect any data from Bubble. It works on its own. If you don't paste your Yandex Metrika Pixel ID, then it wouldn't track any data. If you signed up to Yandex Metrika and got your Pixel ID there, you have agreed with Yandex Metrika Terms of Use and other legal documents and what data they collect. All the documents are listed below. It is almost the same software as Google Analytics.
Hope this description cover all the questions regarding data collection.

Legal documents from Yandex Metrika website:
- GDPR compliance: https://yandex.ru/support/metrica/general/gdpr.html
- Terms of Use: https://yandex.ru/legal/metrica_termsofuse/
- User Agreement: https://yandex.ru/legal/rules/index.html
- Privacy Policy: https://yandex.ru/legal/confidential/index.html