OMG UML Specification
The OMG UML specification (UML Superstructure Specification, v2.1.1, p. 608) states:
An information item is an abstraction of all kinds of information that can be exchanged between objects. It is a kind of classifier intended for representing information at a very abstract way, one which cannot be instantiated.
One purpose of information items is to be able to define preliminary models, before having made detailed modeling decisions on types or structures. One other purpose of information items and information flows is to abstract complex models by a less precise but more general representation of the information exchanged between entities of a system.