- php5-curl Fetching files by HTTP.
- php5-gd Image manipulation (scaling).
- php5-gmp For Salmon signatures (part of OStatus).
+- php5-intl Internationalization support, part of core.
- php5-json For WebFinger lookups and more.
- php5-mysqlnd The native driver for PHP5 MariaDB connections. If you
use MySQL, 'mysql' or 'mysqli' may work.