gnus-cite-unsightly-citation-regexp

gnus-cite-unsightly-citation-regexp is a variable defined in `gnus-cite.el'.
Its value is

"^-----Original Message-----
From: \\(.+
\\)+
"

Documentation:
Regexp matching Microsoft-type rest-of-message citations.

You can customize this variable.

This variable was introduced, or its default value was changed, in version 22.1 of Emacs.