Clarity of Location URL Algorithm

[Redfire75369]

What is the issue with the Fetch Standard?

Under Fetch Spec - Response Location URL Step 3, there is no clear indication for what happens if extracting the header list values gives multiple Location headers.

Say, the response has the following headers:

Location: https://www.example.com/
Location: https://www.example.net/

Although such a response is malformed, it should still be addressed explicitly.
Presumably, the algorithm should return failure in this scenario.

[annevk]

That's correct, if you're willing to help writing tests for this that'd be appreciated. This is tracked by #883 so resolving this as a duplicate.