Far better than Bing or Google. It's not obvious why theirs is so terrible, unless that product is not a moneymaker for them, in which case it explains everything.
Big Russian or Chinese software is even more out of the question than the GAFAMs (if they're big, they definitely have authorities messing with the results).
Hmm, what about Baltic or Ukrainian or Israeli search engines ?
It completely boggles my mind that the useless GitHub and SO clones rank first page on Google. Do engineers at Google not use their own product?
If I am right they played stupid games and won stupid prizes. More specifically they have allowed rampant deletionism for years so while I am fairly certain the questions and answers originated on Stack Overflow it wouldn't surprise me if a good number of of those aren't visible on Stack Overflow anymore which would explain why they rank higher in Google.
Done right this would actually be a service.
Sadly some of them seems to mix together various questions and answers in the same page to generate text matches for unusual queries.
Do you have an example search leading to a GitHub clone?