I have some code that repackages the tz database, and along the way it checks that the subset that it's repackaging is in the public domain. The check is required because not all of the files are PD (some of the man pages are BSD licensed), and the license statement on the automatically-generated package needs to be correct. The code checks by looking for the notices that are at the top of most of the files. I have found that it quite frequently gets broken by small changes in file formatting, or new files with novel format. 2013e broke it by adding leap-seconds.list, and 2013f has just broken it again by adding NEWS. Can we come up with some consistent formatting rules to make the PD notices machine readable? It doesn't have to be a single structure for all file types, just a limited repertoire that code can reliably apply. Or a separate machine-readable list of files with a single statement that the listed files are all PD. -zefram