These days most users don't see a third-party offer in the CCleaner installer - not because it's mysteriously hidden, but because there are some smarter rules set up in the installer not to bother offering something if the user has already seen that offer in the past x months, if they've already got it installed, or (in the case of AV) if they seem to already have an alternative running. (And of course there's no offer with the automatic updates.)