mh-delete-subject-or-thread
mh-delete-subject-or-thread is an interactive autoloaded compiled Lisp function in `mh-limit.el
'.
(mh-delete-subject-or-thread)
Delete messages with same subject or thread.
To delete messages faster, you can use this command to delete all
the messages with the same subject as the current message. This
command puts these messages in a sequence named "subject". You
can undo this action by using u with a prefix argument
and then specifying the "subject" sequence.
However, if the buffer is displaying a threaded view of the
folder then this command behaves like T d.