The Wikipedia articles give a good overview

  https://en.wikipedia.org/wiki/Computer_Corporation_of_America

  https://en.wikipedia.org/wiki/Gosling_Emacs

We had one of the first Pyramid minicomputers, so we got lots of stuff to port.

RMS claimed he modified the earlier, freely redistributable, version of Gosling Emacs, not the one Unipress sold.

The skull and crossbones referenced above is at https://donhopkins.com/home/archive/emacs/skull-and-crossbones.txt

Years later, Lucid forked it (now at xemacs.org) and the personalities involved caused the "great Emacs schism"  A pox on both their houses, I say :)