A Microsoft Group Policy administrative template is a file that supports the implementation of Microsoft Windows Group Policy and centralized user and machine management in Active Directory environments.
Group Policy administrative templates were originally proprietary text markup files with an .adm extension, but Group Policy administration with Windows Vista and Windows Server 2003 and later moved to an XML-based file with an .admx extension. Language-specific administrative templates, such as English or French, are noted with .adml extensions and are placed in language-specific subfolders.Content Continues Below
Administrators use Group Policy to apply certain security or application settings, or implement IT policies on users and machines. The Group Policy administrative templates define the registry settings that administrators can use to manage specific applications.
Group Policy administrative templates can configure the interface and the manner in which those policy settings appear in the Group Policy Object Editor (GPOE) or Group Policy Management Console (GPMC) tools. System administrators use these utilities to create or modify Group Policy Objects (GPOs).
Group Policy administrative templates that manage supported versions of Windows can be downloaded from Microsoft's Download Center. Administrators and software developers can create custom template files to support application development and releases.
The move to an .admx format supported Microsoft's concept of a central store to hold all .admx templates in one location to simplify template management. All .admx files are kept in the %systemroot%\policyDefinitions folder of each local computer by default, and language-specific .adml files are placed into folders beneath that, such as %systemroot%\policyDefinitions\en-us for U.S. English administrative templates.