Technical Summary
This document specifies a Hypertext Transfer Protocol (HTTP) status code
for use when resource access is denied as a consequence of legal
demands.
Review and Consensus
This document started as an individual draft, which the WG discussed and
initially decided to "hold". The primary reason for this was that it
wasn't clear if there were use cases that would benefit from a status
code (as opposed to just using the body of the response), and whether
there was interest in deployment.
Over time, this was clarified; both Web sites and consuming software
demonstrated interest. Importantly, we heard that having an indicator
that an automated client could easily detect would help users like Lumen
<https://lumendatabase.org> (formerly, Chilling Effects).
As a result (and after discussion both on list and in meetings), we
decided to adopt the draft.
Technical discussion involved a broad selection of the Working Group.
There was some back and forth about what the right scope for the status
code's semantics should be (as well as whether we needed more than one),
but we were able to achieve consensus on the current document.
451 has already been adopted by some sites on the Web, and based upon
discussions (mostly private), it appears that a significantly larger
number will adopt it once it becomes standard. On the client side,
interest has been expressed by Lumen, Article19, CDT and others.
Personnel
Mark Nottingham is the document shepherd; Barry Leiba is the responsible
Area Director.