What is extraction template?
An extraction template encodes how a particular site — or a general convention like schema.org metadata — lays out its data, so the fields can be read deterministically. Templates are matched per host and are auto-selected unless you force one by name or disable the library, and the response says which template supplied the result.
Why it matters
A template is the cheapest possible extraction: zero model cost, no hallucination surface, and a stable result across runs. The catalog is public, so checking whether one already covers your target costs nothing and often removes the need for a schema entirely.