First time I'm reading about this, I'm glad there's progress in this area.

The JSON DSL for rewriting emails feels like a spammer/exploit vector waiting to happen. Some product is going to spam filter before applying reconstruction rules, or get tricked into applying reconstruction rules when it shouldn't, and spammers and scammer are going to abuse it.

Until either Google or Microsoft will adopt these standards, they'll remain effectively meaningless most likely. But even so, it's good to know people haven't given up on fixing email's spam problem entirely.