Allow-Cross-Origin-Event-Reporting not defined?

[miketaylr]

Looking at https://github.com/WICG/fenced-frame/pull/152 - I see Allow-Cross-Origin-Event-Reporting referenced, but not defined. I can see that it's parsed as a structured field Item, but doesn't say if it's allowed values are string literals true/false or boolean?0/?1.

https://httpwg.org/specs/rfc8941.html#rfc.section.2 is a useful guide to reference.

[domfarolino]

@blu25