The FAQs page of this extension that is opened in startup has Google Analytics code; This script collects non-personal information (like number of users per country) to improve the web experience of users and notify the website owner of server failures. Note that almost all of the popular websites has this script.
Also note that after successful uninstallation of the extension a feedback form is displayed to collect users feedback. This could help me as the developer to fix issues that has disappointed end users.
Terms can be found here: https://www.google.com/analytics/terms/us.html