ISO 10646
Click on the red underlined text to get to the source
... abstract characters to a set of integers. Examples of coded
character sets are ISO 10646 [ISO-10646], US-ASCII [US-ASCII ...
... registrations SHOULD include a specification of mapping from
the charset into ISO 10646 if specification of such a mapping is
feasible.
...
... URI to a specification of how to translate from
this charset to ISO 10646 and vice versa SHOULD be
provided.)
...
...
Inclusion of a mapping to ISO 10646 is now recommended for all
registered charsets. The registration template ...