says General Tor and Anonymity Forum
https://forums.whonix.org/t/duckduckgo-now-fingerprinting-visitors/6497/4
I see somebody from DDG denies it in that thread. As it stands DDG has built a lot more trust with me than most other search engines so I'm not willing to take the claim from one browser plugin as Holy Writ.
It does pay to keep one's eye out for repeated patterns of dubious behavior so we'll see.
https://news.ycombinator.com/item?id=18839107
The code is apparently innocent wrt privacy, some interesting comments in there though