IMHO Google has been in decline since ~2010 or so, but it's only recently that the dive in quality became very noticeable. Try searching for anything even mildly technical outside of software, and you are presented with pages upon pages of completely irrelevant SEO spam. Automotive repair manuals (for very old cars) are one example; it used to be that you could easily find a link to a PDF, and the results were otherw…
Cloned a git repo where I thought I remembered seeing the function and 500 MB of downloading later grep confirms that I remembered correctly and that the exact keyword I had been searching for is present multiple times in the source code.
My hunch is that since coders use an ad blocker anyway, it's not financially viable to operate source code search on the public internet.