Gremlin Format grn

[Wim Stockman]

Hi , I was looking into the groff doc dir and found this old file format.
the Gremlin file format for graphics.
But even on google I cannot find a lot of information about it.
Does someone have some info on it ,some documentation perhaps
I'd like to take a look at this ancient format out of curiosity.
Kind regards
Wim Stockman