I suggest that IPP/1.1 change, with regard to MIME types, from:
# The value MAY include a charset parameter, depending on the
# specification of the Media Type in the IANA Registry [IANA-MT].
# The value MAY include any number of parameters, depending
# on the specification of the Media Type in the IANA Registry [IANA-MT].
Many media type registrations have both required and optional
parameters. A MIME type which requires a parameter is meaningless
without the parameter, and there are many other parameters other
It is also true that most 'text' types allow a 'charset' parameter,
and you can point this out if you want; the current wording, though,
seems to imply that parameters other than 'charset' are not allowed,
which would be wrong.