The trailing dot makes it an invalid URL, which defines hostname as ∗[ domainlabel "." ] toplabel.
RFC2396§3.2.2 defines hostname as:
hostname = *( domainlabel "." ) toplabel [ "." ]
RFC3986 which obsoletes RFC2396, seems to make fewer claims about the authority section, and specifically says in Appendix D.2 that the toplabel rule has been removed.
RFC2396§3.2.2 defines hostname as:
RFC3986 which obsoletes RFC2396, seems to make fewer claims about the authority section, and specifically says in Appendix D.2 that the toplabel rule has been removed.