Even non-developers are familiar with the 404 – Not Found status code. Some Web application users may have been exposed to more arcane (and sometimes scary) messages like 500 – Internal Server Error, ...

However, status code 451 -- a hat tip to Fahrenheit 451 -- can now be used to distinguish pages unavailable due to censorship.

HTTP status codes are not normally a thing that aids political dissidents, or really anything to get excited about. But the newly-made code 451, to be used when something is taken down for legal ...