The IBM deployment descriptor extensions are additions to the standard descriptors defined in the J2EE specification for J2EE applications, Web applications, and enterprise beans. The extensions allow you to specify properties that enable Enterprise Edition or legacy (older) systems to work in the WebSphere Application Server environment. They also allow you to specify behavior that is vendor specific, undefined in a current specification, or expected to be included in a future specification. Examples of extensions are the MIME-filtering properties of Web applications and the transaction isolation level of enterprise bean methods. Extensions can be found in the ibm-*- ext.xmi files of the module.