mh-ins-buf-prefix

mh-ins-buf-prefix is a variable defined in `mh-e.el'.
Its value is

"> "

Documentation:
*String to put before each line of a yanked or inserted message.

The prefix "> " is the default setting of this option. I
suggest that you not modify this option since it is used by many
mailers and news readers: messages are far easier to read if
several included messages have all been indented by the same
string.

This prefix is not inserted if you use one of the supercite
flavors of `mh-yank-behavior' or you have added a
`mail-citation-hook'.

You can customize this variable.

This variable was introduced, or its default value was changed, in version 6.0 of the MH-E package that is part of Emacs 22.1.