Complex sentence: For PHP 5 and Apache 2.0 on Windows, it is in form of a DLL file called php5apache2.dll, which is a module thatamong other functionsprovides an interface between PHP and the web server, implemented in a form that the server understands.
Split into simpler sentences: For PHP 5 and Apache 2.0 on Windows, it is in the form of a DLL file called php5apache2.dll. That DLL is a module which--among other functions--provides an interface between PHP and the web server, implemented in a form that the server understands.