[freedomben]

I run uMatrix and have noticed some DDG showing up on other sites as well. The sites in question appeared to be (at least ostensibly) using it as a "can I reach the internet" sort of check. If I blocked requests, it would say something to the effect of "no connection detected." I wish I could remember which sites they were, but I do remember seeing at least one call to improving.duckduckgo.com from a 3rd party.

[zodzedzi]

Ok interesting. I'll try to find those sites I encountered again and check it out with uMatrix.

[Havoc]

Isn't umatrix dead/unsupported since like a year or so ago?

[account42]

Unsupported, yes but so far there is no adequate replacement and it remains the best we have.