"The double slash // should always appear in a file URL according to the specification" ([Wikipedia](https://en.wikipedia.org/wiki/File_URI_scheme)). This refers to the actual RFCs, not Apple's documentation (which was apparently written by a single engineer): see [RFC 1738 section 3.10](https://tools.ietf.org/html/rfc1738#section-3.10). I would rather we stick to the official syntax, if possible.