This is a third party extension
FacetWP adds Amazon-like filtering to any WordPress content listing. It allows users to quickly browse and drill-down through your site’s content to find exactly what they’re looking for.
FacetWP includes a “Search” facet, which renders an input box. When configuring a search facet, a “Search Engine” setting lets you choose a SearchWP engine. When a SearchWP engine is selected, the results will be retrieved directly from the SearchWP API.
FacetWP is a 3rd-party plugin. Please contact the FacetWP support team for more information or pre-sales questions.