figForth - 8080 H-89 FORTH V1.12
In a recent acquisition, I received 3 disks labeled "Going Forth - Forth Operating System". These appear to be original distribution disks and included a serial number.
In the disk images, I found "ADAPTED TO HEATH H89 - ZENITH Z89 BY HAYDON ENTERPRISES" From "LA HONDA, CALIFORNIA"
From what I could find about it on the internet, it appears that figForth was placed in the public domain.