gnus-summary-show-article-charset-alist

gnus-summary-show-article-charset-alist is a variable defined in `gnus-sum.el'.
Its value is

nil

Documentation:
Alist of number and charset.
The article will be shown with the charset corresponding to the
numbered argument.
For example: ((1 . cn-gb-2312) (2 . big5)).

You can customize this variable.

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