What does the '@' symbol mean in a URI?

The '@' symbol in a URI is used to separate user credentials (username and password) from the rest of the URI. This is used in schemes that require authentication, such as ftp or http (in some old or specific configurations).

The "userinfo" part format looks like:

user:password@host

Example:

ftp://username:password@ftp.example.com/path/to/file

It is important to note that using passwords in URIs is insecure and not recommended due to potential credential leakage. In most modern web applications and protocols, authentication is performed through other methods (such as HTTP headers, sessions, or tokens), and the use of @ in URIs to transmit credentials is rare.