[tor-dev] Where can I find info for TunnelDirConns 0|1 ?

Dear all, I read a discussion about "How can Tor use a one hop circuit to a directory server during initial bootstrap?" here However, why I cannot find "TunnelDirConns 0|1" in torproject.org/docs/tor-manual.html.en? Is the feature already removed or replaced with another name? Next, may I ask that as  Weasel mentioned in his answer for the question: "This so-called tunneled connection doesn't provide anonymity. It only provides confidentiality, i.e. nobody listening on your network can know exactly what you fetched" However, in Tor directory Protocol 3, there is a sentence "all directory information is uploaded and downloaded with HTTP" which means no encryption for what we fetch, so where is the "confidentiality"? Best Regard.