Long ago, the Linux kernel started using 00-Index files to list the contents of each documentation directory. This was intended to explain what each of those files documented. Henrik Austad recently pointed out that those files have been out of date for a very long time and were probably not used by anyone anymore. This is nothing new. Henrik said in his post that this had been discussed already for years, "and they have since then grown further out of date, so perhaps it is time to just throw them out."
He counted hundreds of instances where the 00-index file was out of date or not present when it should have been. He posted a patch to rip them all unceremoniously out of the kernel.