It's not really an official code integrated into the RFC, it just exists as a proposal.
That said, the code starts with 4, so all browsers will recognize it as the same group of errors of "You're not getting data, sorry chummer." And while not official, the Firefox source code does have it as part of their explicitly called out status codes, so it could be argued that, at least in practice, it's already part of the standard.
It's a really silly status code, though, because now you have a web server / system making legal claims and most probably was not emitted by direct request of a lawyer to make a public statement. Also, 4 is supposed to be for client errors but here the client didn't actually do anything wrong in the request (and certainly has nothing it could possibly do to address it). It's probably better suited as a 5, where the server failed to serve.
It's not really an official code integrated into the RFC, it just exists as a proposal.
That said, the code starts with 4, so all browsers will recognize it as the same group of errors of "You're not getting data, sorry chummer." And while not official, the Firefox source code does have it as part of their explicitly called out status codes, so it could be argued that, at least in practice, it's already part of the standard.
It's a really silly status code, though, because now you have a web server / system making legal claims and most probably was not emitted by direct request of a lawyer to make a public statement. Also, 4 is supposed to be for client errors but here the client didn't actually do anything wrong in the request (and certainly has nothing it could possibly do to address it). It's probably better suited as a 5, where the server failed to serve.