Where are custom .adm files stored in Group Policy Objects (GPOs)?

A. When you create a new GPO, a folder is created under the Domain Controller's (DC's) Sysvol folder (Policies\{} ). Under that structure, a subfolder is created named Adm that has a copy of all the .adm files that are used as Administrative templates, which by default include conf.adm, inetres.adm, system.adm, wmplayer.adm, and wuau.adm. The files total nearly 3.5M, which is a common issue with GPO replication today; these .adm files are replicated between DCs and replicated for every GPO, which can cause a significant amount of traffic if an ADM file is updated).

When you import a new .adm file into the Administrative templates section of a GPO, the .adm file is copied into the GPO's Adm subfolder, which is then replicated via the File Replication Service (FRS) to all other DCs.