[kernelbugs]

b: The author did file a DMCA takedown notice. The issue in this case is that the GitHub user filed a DMCA counter notification which states they have a good faith believe the takedown is incorrect or invalid (under penalty of perjury). I am not a lawyer, but it seems to me that the GitHub user may have perjured themself.

d: One does not need to file any documents in order to have a copyright over a work in the US, it is an automatic right given to creators over their original works. Authors do, however, need to file with the Copyright Office before suing for copyright infringement.