From Google: For some searches, Google provides a quick answer or summary with a content snippet from a relevant website. These featured snippets are most likely to show up when your search is in the form of a question.
About featured snippets
Featured snippets are in a special box at the top of your search results (SERP) with a text description above the link. If you search with the Google Assistant, featured snippets might also be read aloud. Most featured snippets only contain one listing.
Featured snippets include:
- Information quoted from a third-party website
- A link to the page
- The page title
- The URL of the page
The quoted content in featured snippets can be a paragraph, a list or set of steps, or a table.
How featured snippets are chosen
Featured snippets come from web search listings. Google’s automated systems determine whether a page would make a good featured snippet to highlight for a specific search request.