From Dan’s answer to your question a couple of weeks ago, there doesn’t appear to be a physical or visual home/origin:
That being said, creating your own positioning jig should be really simple. Here are a few options…
- Using a set of welding magnets (being very careful not to damage your grid)
- Using a set of 1-2-3 Milling Blocks (depending on the height of your material – don’t let the head impact these)
- Using your Glowforge to cut a jig out of cardboard, acrylic, plywood, whatever
Hope this helps… 
Btw, the GF staff other than Dan doesn’t routinely answer questions on the forums, but the community at large has an amazing body of knowledge that you may find handy. Expressing a desire to have GF staffer answer your question isn’t typically effective…