That might be the case, but I wouldn't use Github search results to confirm this. I have no idea why, as this is super important, but code search in Github is surprisingly terrible. Not sure if this is just me or others have had similar experiences.
Not just you. It can give no results and partial results, which is sometimes fixed on a re-query.
But it also is just poor for code. I think it wants to find full words, so searching for substrings generally results in too few matches. That's made worse by its special character handling in word splitting and query parsing which makes some text impossible to find.