| Lotus Domino Stash Format | |
| IBM | |
| Ads |
File with an .STH extension contains a password to a KYR file stored in a changed format, but not encoded, which was created automatically after generating a set of key-files – KYR, of the Lotus Domino server.
Windows
| .aawdef | Ad-Aware Definitions Format |
| .abr | Adobe Photoshop Brush Format |
| .ac$ | AutoCAD Undo Info Format |
| .acc | DR DOS - ViewMax Format |
| .acl | Microsoft Office Automatic Correction List |
| .acs | Microsoft Agent Character Structured Storage Format |
| .ad | After Dark Screen Saver Format |
| .add | Microsoft Dynamics AX Developer Documentation Format |