I couldnt find the thread that changed it to a "Black" background....

But the original creation from Michael came out of this discussion (I Believe)

https://moi3d.com/forum/lmessages.php?webtag=MOI&msg=10393.2

At that point, it's easier to understand what is being done , then the script background color could easily be changed in here as its just a hex value...

So Somebody just changed the hex value to black, which worked for me, so I saved it as a js file and use it when needed....

You could make 5 or 10 js files with different color backgrounds to use as required in your pipeline.....