Duckduckgo receives tracking parameters

Currently, searching something using DDG from the address bar takes us to https://duckduckgo.com/?t=ffab&q=foo. I assume that ffab stands for "firefox address bar". Similarly, selecting a word, right-clicking, and choosing "Search DuckDuckGo for $word" takes us to https://duckduckgo.com/?t=ffcm&q=foo. Here, I assume that ffcm stands for "firefox context menu". In contrast, searching for something from the search bar on duckduckgo.com takes us to https://duckduckgo.com/?q=foo&t=h_&va=b. va is sometimes a, for some reason. Manually typing https://duckduckgo.com/?q=foo into the addres bar doesn't add any t parameter. The Chromium DDG also takes us to https://duckduckgo.com/?q=foo.

I think we can fix this by removing the in-built DDG search engine from within distribution/policies.json and manually adding a DDG search engine, like we do with Searx, Startpage, etc. We'd want to either have no t parameter, or have t=h.