Yarn bobbins are useful when knitting certain multi-color patterns, to keep the remaining yarn from tangling when it's not enough to stay in a ball.
Inspired by https://www.thingiverse.com/thing:1966606, this design uses less filament and has a more effective clip for the end of the yarn. (This clip design is intended to keep the bobbin from unwinding while the free end of the yarn is attached to your project, not when the end is loose.)
At this thickness, PLA is just flexible enough to make the yarn clips work well.
The author hasn't provided the model origin yet.