With the latest version of Firefox for U.S. desktop users, we’re introducing a new way to measure search activity broken down into high level categories. This measure is not linked with specific individuals and is further anonymized using a technology called OHTTP to ensure it can’t be connected with user IP addresses.

Here’s the current list of categories we’re using: animals, arts, autos, business, career, education, fashion, finance, food, government, health, hobbies, home, inconclusive, news, real estate, society, sports, tech and travel.

Remember, you can always opt out of sending any technical or usage data to Firefox. [...] We also don’t collect category data when you use Private Browsing mode on Firefox.