This is a blade guard for the Super Benriner's No95 Mandoline, so that it's a bit safer to handle while not in use.
It isn't horribly difficult to print, but you may need to keep the layer height <0.2mm for better layer adhesion around the joints.
The snap fit can be a bit stiff, and I'm not super confident about its durability. I'll spend more time tweaking it if it ever breaks on me.
I have also found a blade box for this mandoline on thingiverse. https://www.thingiverse.com/thing:4688676
The author hasn't provided the model origin yet.