The CSS snippet you provided appears to be from a research paper titled , specifically related to the official COCO Dataset website (cocodataset.org).

This code is part of the styling for the COCO Explorer , a tool used to visualize object detection and segmentation masks.

European Conference on Computer Vision (ECCV), 2014. Why the Class Name Looks This Way

The string yRmN2ql0 is likely generated by a CSS-in-JS library (like or Emotion ) or a build tool (like webpack ). These tools minify and unique-ify class names to prevent styling conflicts across large web applications.