array key: filter_button

The filter_button definition defines a submit button where the array keys are text, type, name, wrap and other_attributes. Note that the default values may be different than the default values of the WordPress function, specifically the type of button is not primary but is button. See the WordPress documentation for available values including defaults. The filter_button will submit the form so it is advisable to check for it in the process_bulk_actions callable if there are concerns.

WordPress submit_button documentation is here

$list_table_definitions['filter_button'] = array('text' => "Filter By Make");