src/TaxonomyAdmin.php
public function getList()
    {
        if ($this->modelClass === TaxonomyTerm::class) {
            $list = parent::getList();
            return $list->filter('ParentID', '0');
        }
        return parent::getList();
    }
public function getList()
    {
        if ($this->modelClass === TaxonomyTerm::class) {
            $list = parent::getList();
            return $list->filter('ParentID', '0');
        }
        return parent::getList();
    }
public function getList ( ) { if ( $ this -> modelClass === TaxonomyTerm :: class ) { $ list = parent :: getList ( ) ; return $ list -> filter ( 'ParentID' , '0' ) ; } return parent :: getList ( ) ; }
If terms are the models being managed, filter for only top-level terms - no children

@return SS_List
If terms are the models being managed filter for only top - level terms - no children