[3]Syntax Components
...
The following are two example URIs and their component parts:
foo://example.com:8042/over/there?name=ferret#nose
\_/ \______________/\_________/ \_________/ \__/
| | | | |
scheme authority path query fragment
| _____________________|__
/ \ / \
urn:example:animal:ferret:nose
...
[3.2] Authority
Many URI schemes include a hierarchical element for a naming
authority so that governance of the name space defined by the
remainder of the URI is delegated to that authority (which may, in
turn, delegate it further). The generic syntax provides a common
means for distinguishing an authority based on a registered name or
server address, along with optional port and user information.
The authority component is preceded by a double slash ("//") and is
terminated by the next slash ("/"), question mark ("?"), or number
sign ("#") character, or by the end of the URI.
authority = [ userinfo "@" ] host [ ":" port ]
URI producers and normalizers should omit the ":" delimiter that
separates host from port if the port component is empty. Some
schemes do not allow the userinfo and/or port subcomponents.
If a URI contains an authority component, then the path component
must either be empty or begin with a slash ("/") character. Non-
validating parsers (those that merely separate a URI reference into
its major components) will often ignore the subcomponent structure of
authority, treating it as an opaque string from the double-slash to
the first terminating delimiter, until such time as the URI is dereferenced.
[3.5] Fragment
The fragment identifier component of a URI allows indirect
identification of a secondary resource by reference to a primary
resource and additional identifying information. The identified
secondary resource may be some portion or subset of the primary
resource, some view on representations of the primary resource, or
some other resource defined or described by those representations. A
fragment identifier component is indicated by the presence of a
number sign ("#") character and terminated by the end of the URI.
fragment = *( pchar / "/" / "?" )
## developer.mozilla.org
> A URL is composed of different parts, some mandatory and others optional. The most important parts are highlighted on the URL below (details are provided in the following sections):
>
https://developer.mozilla.org/en-US/docs/Learn/Common_questions/Web_mechanics/What_is_a_URL
rfc3986: Uniform Resource Identifier (URI): Generic Syntax
https://www.rfc-editor.org/rfc/rfc3986#section-3
[3.2] Authority
Many URI schemes include a hierarchical element for a naming authority so that governance of the name space defined by the remainder of the URI is delegated to that authority (which may, in turn, delegate it further). The generic syntax provides a common means for distinguishing an authority based on a registered name or server address, along with optional port and user information.
The authority component is preceded by a double slash ("//") and is terminated by the next slash ("/"), question mark ("?"), or number sign ("#") character, or by the end of the URI.
URI producers and normalizers should omit the ":" delimiter that separates host from port if the port component is empty. Some schemes do not allow the userinfo and/or port subcomponents.
If a URI contains an authority component, then the path component must either be empty or begin with a slash ("/") character. Non- validating parsers (those that merely separate a URI reference into its major components) will often ignore the subcomponent structure of authority, treating it as an opaque string from the double-slash to the first terminating delimiter, until such time as the URI is dereferenced.
[3.5] Fragment
The fragment identifier component of a URI allows indirect identification of a secondary resource by reference to a primary resource and additional identifying information. The identified secondary resource may be some portion or subset of the primary resource, some view on representations of the primary resource, or some other resource defined or described by those representations. A fragment identifier component is indicated by the presence of a number sign ("#") character and terminated by the end of the URI.