CloudFlare: 94 Percent of Tor Traffic Is Malicious

To tell the truth, only yacy and sightnet have own index(database). Others are meta-search engines. They work like proxy. It's called meta search. (https://en.wikipedia.org/wiki/Metasearch_engine)

Ok, i'll add it. Thanks.

But duckduckgo is not open source project.

I was wrong.

The search results provided by Mojeek come from its own index of web pages, created by crawling the web.[6][7][8]

Yes, Qwant uses bing api(like ddg).

So, ddg and brave also have own indices. But i dont think, that it is matter, anyway they send data to 3rd party services.

Sorry, i have no much time to write docs. Would you like to contribute?

I should have specify, that they don't block only tor. They block malicious traffic.