RFC 7725, "An HTTP Status Code to Report Legal Obstacles", February 2016Source of RFC: httpbis (art)
Errata ID: 5181
Reported By: Stéphane Bortzmeyer
Date Reported: 2017-11-11
Section 3 says:
Link: <https://spqr.example.org/legislatione>; rel="blocked-by"
It should say:
Link: <https://search.example.net/legal>; rel="blocked-by"
Of course, it is hard to say from just an URL but it seems that the original "blocked-by" mentioned the authority requesting the blocking (spqr = Roman Senate and People) while the text in section 4 says "The intent is that the header be used to identify the entity actually implementing blockage, not any other entity mandating it."
Experience with the 451 crawler during the IETF 99 hackathon showed that several implementors got this wrong and used a "blocked-by" indicating the authority.
[It could be a good idea to have two links, one for the authority and one for the implementor, but this is outside the scope of this errata.]