header
  The file "header" contains the basic licensing statement, which is
  included with most of the source code (.cc, .c, .h) files in the
  distribution.

LICENSE-2.0.txt
  The Apache-2.0 license under which this distribution is released. 
  In some cases, not all provisions of the Apache license are
  available due to constraints imposed by the licensing of earlier
  work from which the file was derived.  In this case, the file will
  contain a sub-header specifying the licensing terms.

newhdr
  A script for stripping/adding new header text.