Most configuration values should be written in parameters. But for some tasks the most efficient way to store configuration values is a PHP file. As an example we will take TinyMCE editor config. It will be really hard to configure TinyMCE plugins and other options in browser. For this task ImpressPages has special system. All configuration files can be overridden. If you find a configuration file that you need to override, simply copy it from original location to according location in ip_configs directory and change anything you need in duplicated file.