Should 0.0.0.0 always be a network error?

[annevk]

See discussion in WICG/private-network-access#24.

(Maybe wait until #1118 is fixed before fixing this.)

[letitz]

I'd be in favor of such a move - it makes the web platform more interoperable given that behavior currently differs between OSes.

[letitz]

@iVanlIsh has added a use counter to Chrome 102 in order to estimate usage of 0.0.0.0. So far, usage seems pretty low - around 0.002% of total page loads in Beta: https://chromestatus.com/metrics/feature/timeline/popularity/4203. We're waiting to see how the data looks in stable, but it seems that a straight deprecation would be feasible.