The copyright and license notice is already in the LICENSE file. There
is no justifiable reason to also require that it be included in every
file, since the individual files are not individually distributed except
as part of the entire package.
This allows the various fs utilities and process.umask to be used in
ECMAScript 5 Strict Mode, where the octal literal format is verboten,
without requiring users to litter their code with a bunch of parseInt
calls.