305 Use Proxy
305 Use Proxy is a deprecated status code. Using the status-code a
server could instruct a client that it should connect to a proxy, and repeat
that same request there.
305 kind of works like a redirect. It really tells a client: this resource
can only be fetched if you used the right proxy. Presumably a client could
connect to this proxy and via the proxy try the exact same request again to
get the real response.
305 Use Proxy is deprecated due to security concerns. It shouldn’t be used.
I’m not aware of any implementors, although they might be out there.
The following response would tell a client that it should attempt the same
request again via a proxy on
HTTP/1.1 305 Use Proxy Location: https://proxy.example.org:8080/