AntiSamy module comes bundled with the default AntiSamy settings/definition.
Tuning the settings
Those default settings accommodate to most general use. However there are many times where some minor changes will be required to fit the business needs.
In order to override the definition, a tuned xml must be inserted into the saml bundle (com.liferay.portal.security.antisamy.jar) and specify the new path in "System Settings > AntiSamy Sanitizer > Configuration File URL".
In order to customize AntiSamy settings, messing with the module's jar file is cumbersome and have the risk of losing the custom settings when updating to newer fixpacks or hotfix.
"Configuration File URL" should allow reading the data from an XML outside the module providing an absolute path.