Zvezdochka's Ergonomic Handle

[Dr. Penguin]

As I was trying to explore new weapon, I found that the location of the blueprint of Zvezdochka's Ergonomic Handle is not listed on any test ground.
Does anyone know where and how to get it?

[Homeless.]

I found it in a small shack in the first open world area behind the solar system, all the way south from where the maglev crashed