Error
Authentication
What the sign-up form has to render
Whether creating an account on this server demands a solved captcha, and the public key that draws one.
Public and cacheable — it reads nothing, and a site key belongs in page HTML by design. required is already the conjunction of “this server asked for a challenge” and “this server has a provider to check it with”, so a form never renders one that could not be verified.
Cache-Control: public, max-age=60, stale-while-revalidate=600, stale-if-error=600.
GET
Error
Response
The sign-up form's requirements.