File Extensions (PHP and Corel Paradox Cross Reference Guide)

.php is the default extension for PHP although some developers will change the default extension in an effort to add an additional security level. If your code is tied to a particular version of PHP then some developers at the major PHP version number to the extension as in .php3, .php4, .php5, etc. 

.phtml is also sometimes used especially for files that contain both HTML and Perl code.

Paradox for Windows has two primary file types: source files and delivered files:

Source Files
Source files in Paradox are binary but can can be opened in later versions of Paradox and even in earlier versions if you don't use any new features.

• .FSL = Form
• .RSL = Report
• .SSL = Script
• .LSL = Library

Since Paradox source files do not compile to an EXE, Paradox developers tend to use a startup form or script to start the application.

 ObjectPAL File Extensions