nostr:npub1q6pnfvhee40rpdpcvmztvz7nzg6w9xlfhsgmq6hsxlkzfr0577hq47vdy9, there were a old thread about this (the "ghost" guy was Jeff, the Krux creator)

https://github.com/selfcustody/krux/discussions/189

It were implemented once as experiment, but now Krux is a Bitcoin's signer only

(but we talk sometimes to follow the 1 or 2 item described in the link above).