But to you -- the user entering credentials -- that error message is still accurate. From GitHub's perspective, they don't know which one you entered correctly.

But to you -- the user entering credentials -- that error message is still accurate. From GitHub's perspective, they don't know which one you entered correctly. It could be argued they should tell you that the username doesn't exist if it doesn't (reasonable with public profile), but in the case of an existing user, this is the only correct error message.