Knowledge panel

Its presence tells you Google treats the subject as a thing rather than a phrase.

Intent is assigned when a query enters the corpus, so this split does not drift as results change.

Every query in the corpus is run once a week through one endpoint, from the United States, in English, with autocorrect on. A block counts as present when the response contains it — Google omits the key entirely when it renders nothing, so presence is unambiguous rather than inferred from an empty array.

curl --request GET \
  --url 'https://serpens.p.rapidapi.com/api/v1/search_ai_overview?q=what%20is%20retrieval%20augmented%20generation&gl=us&hl=en&format=json' \
  --header 'x-rapidapi-host: serpens.p.rapidapi.com' \
  --header 'x-rapidapi-key: YOUR_KEY'

Other blocks: ai overview, people also ask, related searches, sitelinks.