ibuffer-filter-format-alist

ibuffer-filter-format-alist is a variable defined in `ibuf-ext.el'.
Its value is

nil

Documentation:
An alist which has special formats used when a filter is active.
The contents of this variable should look like:
((FILTER (FORMAT FORMAT ...)) (FILTER (FORMAT FORMAT ...)) ...)

For example, suppose that when you add a filter for buffers whose
major mode is `emacs-lisp-mode', you only want to see the mark and the
name of the buffer. You could accomplish that by adding:
(mode ((mark " " name)))
to this variable.

You can customize this variable.