It's a strange directory because it mix the old and the new implementation of Racket. But IIUC you are not looking at the internal content of the files, only the size. Perhaps you can fill a bug report in the d3.js package. (I'm not sure it's a bug, or just a very weird case.)

In the part that says "direct link to your own repository" you can add a link icon for people (like me) that doesn't read all the text. (I was going to suggest that as a feature, but looking again I found it.)