There's effort to define standard behavior here. See https://wicg.github.io/priv...

		dwaite 64 days ago \| parent \| context \| favorite \| on: Covert web-to-app tracking via localhost on Androi... There's effort to define standard behavior here. See https://wicg.github.io/private-network-access/ (although I suspect this document may make a significant shift soon)