.PHP3 File Extension
What is a PHP3 file?
Web page that may contain PHP 3 code; the PHP code within the page is parsed by a PHP engine on the Web server, which dynamically generates HTML that is sent to the user's Web browser; often used in combination with a database, such as MySQL.
PHP3 pages can be processed by Apache, Windows Server, or Mac OS X Server with the PHP engine installed. They can be edited with a text editor or Web development program.
PHP pages generally use the .PHP file extension.