The directory structure of pear-core/
    matches that of the install tree (by default
    /usr/local/lib/php), and are organized as a
    simple hierarchy.  However, the directory structure of
    pear/ is based on what package the files
    belong to.  Where files are located in each package directory is
    completely independent from where they end up being installed,
    this is all determined by the package description file.