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-naut is for roles that describe a specific headmate's experiences during fronting or with the shared reality. It is exclusive to headmates that front — excluding insiders, for example.[1]
While there doesn't appear to be a coining post for the -naut suffix in particular, the terms outernaut and perinaut were coined by Tumblr user futurehopecollective on May 26th, 2021.[2] No flag has since been made.
It comes from "astronaut", an explorer of new places and expanding horizons.