Gopher

The first character of the URL path (after the initial single slash) is a single-character "type" field which is that used by the Gopher protocol. The rest of the path is the "selector string", with disallowed characters encoded. Note that some selector strings begin with a copy of the gopher type character, in which case that character will occur twice consecutively in the URL. If the type character and selector are omitted, the type defaults to "1". Gopher links which refer to non-Gopher protocols are represented directly as URLs of the underlying access method and are not represented as Gopher URLs.

[Whether extensions are required, and if so what, for Gopher+ is under discussion, and a new draft exists.. - tbl 3/93]