RFC 2396 is obsolete.
For modern versions of the spec, see:
- RFC3987 (in relation to IRI’s); and
- RFC3986 (in relation to URI’s).
About /
Yes, that is used as a delimiter in the path part.
About :
Ye, it is used as a prefix for port, but it has other roles such as the user info separator, and a delimiter for IP styles of host specifiers.
About =
Suprisingly, the = character is not part of the general URL, URI nor IRI syntax. It has a special meaning only the the http(s) protocols. This is not intrinsic to URL/IRI/URI
About +
The role of + as a substitute for space is NOT part of the URL/URI/IRI syntax. It is merely a convenient invention of some PHP programs for pretty URL purposes.
About $ and ;
These have no special meaning in the URL/URI/IRI syntax. They can be part of the sub-delimiters production, which can be used in the user info part, future-IP part, path segment or a host part.