have you used google's internal code search though? the link you posted is amazing in its performance, for sure. but once you are in some repo and doing what most of us call "code search", github drops off in utility vs google's internal tooling pretty quickly.
i'm only remarking on this because of the context in the parent you are replying to, whom i agree with. local tooling is better than what github provides. as a standalone comment i would simply upvote you.
Chances are that a random stranger on the Internet has not used Google's internal code search. Even if that person has, it would be useful to provide the context for others to understand.
Local code search is great in JetBrains products. I use PyCharm and even on large codebases the search is almost instantaneous and there are enough filters and options to nail down what you need. While JetBrains often drops the ball on the responsiveness of their products, the search remains fast as far (and as recent) as I remember.
I've used both. Google's code search is usually better if you know what you're looking for. It's less so if you need to do something that involves cross-language references (e.g. code file that references a translation string).
i'm only remarking on this because of the context in the parent you are replying to, whom i agree with. local tooling is better than what github provides. as a standalone comment i would simply upvote you.