Pear

Pear is a mechanism to install PHP modules automatically with resolving dependencies. Compare cpan. The actual software is stored in /usr/share/php5/PEAR:

/usr/share/php5/PEAR # ls
.channels   .filemap   Archive  MDB2.php  OS        PEAR5.php   XML   pearcmd.php
.depdb      .lock      Console  Mail      PEAR      Structures  data  peclcmd.php
.depdblock  .registry  MDB2     Net       PEAR.php  System.php  doc   test