Smile\ElasticsuiteTracker\Block\Variables\Page\Catalog::getLayerVariables PHP Method

    private function getLayerVariables()
    {
        $variables = [];
        $layer = $this->catalogLayer;
        if ($layer) {
            $layerState = $layer->getState();
            foreach ($layerState->getFilters() as $currentFilter) {
                $identifier = $currentFilter->getRequestVar();
                if ($currentFilter->getFilter()) {
                    $identifier = $currentFilter->getFilter()->getRequestVar();
                }
                $filterValue = $this->getRequest()->getParam($identifier, '');
                if (is_array($filterValue)) {
                    $filterValue = implode('|', $filterValue);
                }
                $variables['product_list.filters.' . $identifier] = $filterValue;
            }
        }
        return $variables;
    }