src/Controller/Component/ListFilterComponent.php
public function getFilters()
    {
        $filters = [];
        if (method_exists($this->_controller, 'getListFilters')) {
            $filters = $this->_controller->getListFilters($this->_controller->request->action);
        } elseif (isset($this->_controller->listFilters) && !empty($this->_controller->listFilters[$this->_controller->request->action])) {
            $filters = $this->_controller->listFilters[$this->_controller->request->action];
        }
        if (empty($filters)) {
            return [];
        }
        foreach ($filters['fields'] as $field => &$fieldConfig) {
            if (isset($fieldConfig['type']) && $fieldConfig['type'] == 'select'
                && !isset($fieldConfig['searchType'])
            ) {
                $fieldConfig['searchType'] = 'select';
                $fieldConfig['inputOptions']['type'] = 'select';
                unset($fieldConfig['type']);
            }
            // backwards compatibility
            if (isset($fieldConfig['type'])) {
                $fieldConfig['inputOptions']['type'] = $fieldConfig['type'];
                unset($fieldConfig['type']);
            }
            if (isset($fieldConfig['label'])) {
                $fieldConfig['inputOptions']['label'] = $fieldConfig['label'];
                unset($fieldConfig['label']);
            }
            if (isset($fieldConfig['searchType'])
                && in_array($fieldConfig['searchType'], ['select', 'multipleselect'])
            ) {
                if (!isset($fieldConfig['inputOptions']['type'])) {
                    $fieldConfig['inputOptions']['type'] = 'select';
                }
                if (!isset($fieldConfig['inputOptions']['empty'])) {
                    $fieldConfig['inputOptions']['empty'] = true;
                }
            }
            $fieldConfig = Hash::merge($this->defaultListFilter, $fieldConfig);
        }

        return $filters;
    }
public function getFilters()
    {
        $filters = [];
        if (method_exists($this->_controller, 'getListFilters')) {
            $filters = $this->_controller->getListFilters($this->_controller->request->action);
        } elseif (isset($this->_controller->listFilters) && !empty($this->_controller->listFilters[$this->_controller->request->action])) {
            $filters = $this->_controller->listFilters[$this->_controller->request->action];
        }
        if (empty($filters)) {
            return [];
        }
        foreach ($filters['fields'] as $field => &$fieldConfig) {
            if (isset($fieldConfig['type']) && $fieldConfig['type'] == 'select'
                && !isset($fieldConfig['searchType'])
            ) {
                $fieldConfig['searchType'] = 'select';
                $fieldConfig['inputOptions']['type'] = 'select';
                unset($fieldConfig['type']);
            }
            // backwards compatibility
            if (isset($fieldConfig['type'])) {
                $fieldConfig['inputOptions']['type'] = $fieldConfig['type'];
                unset($fieldConfig['type']);
            }
            if (isset($fieldConfig['label'])) {
                $fieldConfig['inputOptions']['label'] = $fieldConfig['label'];
                unset($fieldConfig['label']);
            }
            if (isset($fieldConfig['searchType'])
                && in_array($fieldConfig['searchType'], ['select', 'multipleselect'])
            ) {
                if (!isset($fieldConfig['inputOptions']['type'])) {
                    $fieldConfig['inputOptions']['type'] = 'select';
                }
                if (!isset($fieldConfig['inputOptions']['empty'])) {
                    $fieldConfig['inputOptions']['empty'] = true;
                }
            }
            $fieldConfig = Hash::merge($this->defaultListFilter, $fieldConfig);
        }

        return $filters;
    }
Formats and enriches field configs

@return array