These are tools for scraping out small spaces or scraping small detail on surfaces… like your 3D prints. There are two types in each size. On one, instead of a small curve, it will have a straight end.
CAUTION These tools have VERY SHARP pointed ends. They should be used and stored with care. All plastic tools have their breaking point. Wear appropriate eye protection.
The original 3mm tool I made was for cleaning out the remnants from screen spline grooves. I figured I would make a full set and add a Spudger to replace my aging ones.
PLA works but remember it is brittle. I add extra surfaces and fill to just the ends.
I usually print at .15 with a .4 nozzle.
The author hasn't provided the model origin yet.