Unclear how to serialize request origin "client"

[Wuelle]

What is the issue with the Fetch Standard?

When serializing a request origin, Step 2. tells us to
Return request's origin, serialized. A request's origin is either "client" or an Origin. However, the

ASCII serialisation of an origin algorithm referenced in Step 2. does not handle the case of a "client" origin. (Because it is about serializing an origin as described in the HTML spec, not a request's origin as described in the fetch spec.)

How should an origin of "client" be serialized?

[annevk]

I don't think it can ever be "client" at that point in time? Might be reasonable to add an assert though.