Yes Smoothieware is open source. No that modification has not been published either in edge or other branches. And it you follow the link you posted, you’ll see a dropbox link to a compiled firmware (binary). This is closed source, since it contains improprement not published and is shipped only as a binary.
First question is still opened : where is the source code !
And that question seems to be for @LightBurn , who seemed to write both parts of code (Lightburn AND Cohesion3D) and was paid for it by Cohesion3D.
Yours,
JPC