| ddr | MAP Parameterisation Document |
| ddrt | LeCroy DDR Trace Data |
| dds | MAP Service Document |
| ddt | Oracle Documaker GenData Dataprocessing Rules Data |
| ddu | MAP dlms User Association Document |
| ddy | ASHRAE Design Conditions Design Day Data |
| dea | Drug Enforcement Administration Data |
| debuglog | MyDefrag Debug Log |
| dee | Creator Circuit Description File |
| def | SmartWare Definition Data |
| deform | FontTwister Deform Guide Line Data |
| defxml | Danea Easyfatt Data |
| dei | Gerber Design Engineered Interface Data |
| dek | Memorize-It Deck File |
| del | Lucene Deleted Documents Data |
| delta | Firebird SQL Delta Data |
| dem | SOBEK Digital Elevation Map Data |
| dem | Vflo Digital Elevation Model Data |
| den | XMVB Density Data |
| deos | Driver Easy Offline Scan Data |
| dep | HAHTsite Project Dependencies Data |
| deploy | ClickOnce Deployment Data |
| desg | Stuffit DropSegment Data |
| dess | Microsoft Device Emulator Saved State Data |
| det | Act! Email Message |
| deu | Adobe Acrobat Reader German Language Data |
| dev | Railway Operation Simulator Development Data |
| devx | E-Sword Devotional Data |
| dez | DataEase v4 Data File |
| df | Lightscape Parameter File |
| df | Paradox Table Filter |
| df10 | IRIG 106 Recording Directory Data |
| df7 | Omnis Studio v7 Database |
| dfa | SecuROM Manual Activation Request. |
| dfd | Oracle Documaker Data Field Definition Data |