These are label separators for easy distinction between different kinds of filaments in filament swatch setups (24x24mm), like for example https://makerworld.com/en/models/96463 (as displayed on the photos) or https://makerworld.com/en/models/188119. The printed short text on each separator makes sure you can quickly find what you are looking for.
Print at 0.2 layer height and use a different filament for the last 2 layers.
There is another version as well that doesn't protrude at the top that will fit under a cover for the gridfinity box.
This contains all current material tags for Bambulab filaments. Please reach out in the comments for other brand requests.