The extension does not collect any data of any kind. It's all done locally.

The extension doesn't embed any kind of analytic hooks in its code. The only data provided to me are collected by Firefox. A set of aggregated statistics from Firefox telemetry data that don't include any personally identifiable user data. It's all about user adoption, general demographics, and other insights that might help to make changes or improvements.

In reality, I don't need it, it just remembers me that I might need to implement an internationalization and localization feature if I need to create an user interface for the extension one day.

Here the list of datasets:

• Downloads by
  
  • by Source
  • by Medium
  • by Content
  • by Campaign
• Daily Users
  
  • by Add-on Version
  • by Application
  • by Language
  • by Platform
  • by Country

Mozilla allows you to fully control this telemetry system and more can be found here.

The project is currently hosted on github.com, owned by the subsidiary of Microsoft Corporation named GitHub Inc.