.dev is not an internal Google TLD. It is delegated but not yet launched (i.e. made available for registration). We don't use it for anything internally.

You should not be using globally delegated TLDs for local testing. See RFC 2606. I don't see how using .localhost or .test is any more of an inconvenience than using .dev. Indeed it is less of an inconvenience because it will work without DNS shenanigans.

The last round of gTLD expansion occurred in 2012 and there's still many years left until a potential future round. Additionally, .vm is not a valid gTLD because all two letter combinations are reserved for ccTLDs (countries).

And I would love to have some plans to announce. Maybe soon.