mh-tick-seq

mh-tick-seq is a variable defined in `mh-e.el'.
Its value is

tick

Documentation:
The name of the MH sequence for ticked messages.

You can customize this option if you already use the "tick"
sequence for your own use. You can also disable all of the
ticking functions by choosing the "Disable Ticking" item but
there isn't much advantage to that.

You can customize this variable.

This variable was introduced, or its default value was changed, in version 7.3 of the MH-E package that is part of Emacs 22.1.