ibuffer-saved-filter-groups

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

nil

Documentation:
An alist of filtering groups to switch between.

This variable should look like (("STRING" QUALIFIERS)
("STRING" QUALIFIERS) ...), where
QUALIFIERS is a list of the same form as
`ibuffer-filtering-qualifiers'.

See also the variables `ibuffer-filter-groups',
`ibuffer-filtering-qualifiers', `ibuffer-filtering-alist', and the
functions `ibuffer-switch-to-saved-filter-groups',
`ibuffer-save-filter-groups'.

You can customize this variable.