XML tags represent the kind of content being posted and transmitted .. This statement is true for Extensible Markup Language (XML).
Extensible Markup Language (XML) is a markup language that defines a set of rules for encoding documents in a format that is both human-readable and machine-readable.
Developers of applications should note that the XML standard allows developers
and writers to invent different elements they need as required and defines a generic syntax used
to mark up data utilizing human-readable tags.
Hopt this will help you.