| Windows Port Device Driver Format | |
| N/A | |
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PDR extension is used by Windows port, interface, and device drivers. PDR files are used by the system for recognizing devices attached to the computer. PDR file is a type of system file.
| .adm | Administrator Policy Template Format |
| .adml | Microsoft Administrative Language-specific XML Template Format |
| .admx | Microsoft Administrative XML Template Format |
| .aml | Microsoft Assistance Markup Language |
| .ani | Animated Cursor |
| .ann | Microsoft Windows Help Annotation Format |
| .aos | Archos Signed Encrypted Data Format |
| .asec | Google Android Encrypted Application Package Format |