Testnet4 on the roadmap?

I see the node supports mainnet / testnet3 / regtest — are there plans to add testnet4? It's not just a new genesis: BIP94 changed the difficulty rules (the timewarp fix), so it needs its own handling.

For context: bitcoin-desktop/schema is a JSON-LD model of the protocol with a declarative validation ruleset, light-client focus — it validates testnet4 from genesis, so a different layer from your full node. Happy to compare notes. Thanks for the work.