So apparently, the Internet Engineering Task Force is going to introduce a new HTTP status code. Just like there's the 404 for "File not found", we're soon going to have "397 Tolerating", similar to a redirect.
The way it would work is, if you send a request that violates some standard, but the server can identify the probable intent of your request, it will reply with a "397 Tolerating" to say, "oh, you messed up, and here's how, but I'm going to reply to what I think you meant".
This is much better than the options we had before, which were either a) unnecessarily reject the request, or b) silently reply to the intended meaning but with no notice that was happening. This lets you tell the client you're tolerating their garbage!
My contact at IETF send me an early draft of the RFC, which you can access at the link below.
RFC 8969: HTTP Status Code 397: Tolerating