Group policy administrative templates are a xml based file with admx file extension. The language specific template files have the adml file extension. In the GPMC administrative template are found in the Computer or User section / Policies / Administrative Templates.
Administrative templates allow administrator to define registry settings that control programs. The computer section of GPO modifies HKEY_LOCAL_MACHINE and user section modifies HKEY_CURRENT_USER in the registry.
The admx files are kept in %systemroot%\policyDefinitions folder at each computer and the adml files kept in %systemroot%\policyDefinitions\en-us for U.S. English.
A central store in Active Directory can be created so that each Domain Controller uses that store instead of each individual computer store. This is done by copying the PolicyDefinitions folder from %systemroot% to \\compan.local\SYSVOL\company.local\policies
Windows 2012 has a number of powershell cmdlets for group policy, these include:
Backup-GPO -Backup one or all of the GPOs
Import-GPO -Imports a backed up GPO
Copy-GPO -Copies a GPO
Get-GPInheritance -Gets Group Policy inheritance information for a specified domain or OU.
New-GPO -Creates a new GPO
New-GPOLink -Link a GPO to OU or Domain