message-subject-re-regexp
message-subject-re-regexp is a variable defined in `message.el'.
Its value is "^[ ]*\\([Rr][Ee]\\(\\[[0-9]*\\]\\)*:[ ]*\\)*[ ]*"Documentation: *Regexp matching "Re: " in the subject line. You can customize this variable.
message.el'.
Its value is "^[ ]*\\([Rr][Ee]\\(\\[[0-9]*\\]\\)*:[ ]*\\)*[ ]*"Documentation: *Regexp matching "Re: " in the subject line. You can customize this variable.