X-token in text-subtype

Why is it not defined a x-token in the text-subtype?
As it is now if you want to use local character sets you
have to define Content-Type: x-text/my_character_set instead of
Content-Type: text/x-my_character_set.  Other content-types
allows the x-token syntax in the subtype.

Sven-Ove Westberg, CAD, University of Lulea, S-951 87 Lulea, Sweden.