Documenting release contents
   In package.xml 1.0, the contents tag was <filelist>.  The purpose of the
   tag changed dramatically in package.xml 2.0, warranting a name change.  Now, <filelist>
   can be found in the release section
   of the package.xml.
  
   <contents> is used to describe the contents of a tarball.  Nothing further.  All
   files in the contents tag will be placed into the tarball regardless of whether they
   eventually get installed by the PEAR installer.  This fact can be used to create a very
   versatile tarball, one that can be directly unzipped and work out of the box as well as
   be installed by the PEAR installer and work out of the box.
  
   For most release types, contents contains a single <dir> tag that then either
   contains nested dir tags and/or <file> tags.