gnus-newsgroup-ignored-charsets

gnus-newsgroup-ignored-charsets is a variable defined in `gnus-sum.el'.
Its value is

(unknown-8bit x-unknown)

Documentation:
List of charsets that should be ignored.
When these charsets are used in the "charset" parameter, the
default charset will be used instead.

You can customize this variable.

This variable was introduced, or its default value was changed, in version 21.1 of Emacs.