Thanks for response.

GeorgeWest.
I realized that I had made such a right angle jigs many times. But indeed from wood, and I threw it away every time.

PapaDave.
Ken has got a mail with link.

Jim Jakosh
I didn't really think about how to make it because honestly it's a copy. I did attach a measuring tape as an extra, but more because I still had it lying around.

https://dutchypatterns.com/