Just a simple 4 part print with hinge at the back sized for a M3 x 20mm.
Might need glue depending on tolerance.
I printed the bottom open side down with a support raft with a 0.2 gap and dense top interface layer. You can also print it open side up and sink it into the build plate a couple mm if you want it to stand on its own.
The ring I printed as it lands on the plate pins up with the same support setting.
The author hasn't provided the model origin yet.