This extension sends the data of the page (such as page url, page title, selected text, the text around of selected text) that you are viewing to LinguaLeo in order to get it translated or to add it to the LinguaLeo's dictionary. If the text you select to look up or the page you want to translate contain sensitive personal information or data, they will be sent to LinguaLeo too. You should read their Terms of Use:
https://corp.lingualeo.com/ru/termsofuse/

By using this extension, you agree that you are aware of and accept this behavior and any other terms and conditions of the extension. If you do not agree to the terms and conditions of this extension, please do not use it.