The Internet Engineering Steering Group, which is a part of the IETF, has approved a new HTTP status code, 451 Unavailable For Legal Reasons. This new status code is to be used when a website can't be displayed because of legal issues and in this way, offer more transparency towards censorship on the internet.
The proposal for the new status code has been made by the 451 Unavailable group, which is a group that tries to make censorship on the internet more clearly visible. The reason for this proposal was that with this code, developers and ISP's can provide clarity into why a website isn't available.
This new error code shows that a website is not available because of it being legally blocked or deleted in a country. Right now, for these kinds of errors, the regular error code 403 is used, which stands for "Forbidden Access". This code, however, doesn't cover what is really happening, and the 451 Unavailable group finds that a new error code will add more clarity to this.
The number 451 is a reference to the book Fahrenheit 451 by Ray Bradbury. In the story of this book, censorship is very common and books are forbidden.
The usage of this new code is not mandatory and as such it will be up to the developers to implement this, meaning that while this error code can clear up a lot of confusion, it will never cover all legally blocked content. It's also still possible for governments to try and block this error message out by forcing sites to return a 403 error message. However, it does look like this is a step in the right direction.