MediaWiki directory structure

The directories that the MediaWiki installation bring look like this:

/etc/mediawiki
/usr/share/doc/mediawiki
                |-- docs
                |   |-- html
                |   `-- php-memcached
                `-- examples
/usr/share/mediawiki
           |-- includes
           |   |-- api
           |   |-- cbt
           |   |-- filerepo
           |   |-- media
           |   |-- normal
           |   |-- templates
           |   `-- zhtable
           |-- languages
           |   |-- classes
           |   `-- messages
           |-- maintenance
           |   |-- archives
           |   |-- dtrace
           |   |-- language
           |   |-- ora
           |   |-- postgres
           |   |   `-- archives
           |   `-- storage
           `-- skins
               |-- chick
               |-- common
               |   `-- images
               |       `-- icons
               |-- disabled
               |-- modern
               |-- monobook
               |-- myskin
               `-- simple
/var/lib/mediawiki
         |-- config
         |-- extensions
         `-- images