| ctb | BRLTTY Contraction Table Data |
| ctf | AVG Update Control File |
| cti | BRLTTY Contraction Table Include Data |
| cui | Autodesk AutoCAD Custom Workspace |
| cwc | CADfix Wizard Configuration Data |
| cwl | TeXstudio Completion Word List |
| cwy | ChordWizard Songtrix Style |
| cw_ | CorelDraw Workspace Description Data |
| cxr | CX-Programmer Settings Data |
| cxz | PND Scanner Configuration |
| cyberduckprofile | Cyberduck Connection Profile Data |
| d2r | DEM2RWX Saved Settings |
| dapf | Dinkey Pro/FD DinkeyAdd Parameter Data |
| db | CA-dBFast Database Configuration |
| db7 | Casio WK-3000 User Drawbar Organ Tones |
| dbgdt | IAR Embedded Workbench Debugger Settings |
| dbh | CodeWarrior Debug Preferences |
| dbl | DAZ Brick Light |
| dc0 | OpenBSD Interface Configuration Data |
| dc1 | OpenBSD Interface Configuration Data |
| dcc | Nokia Dynamic Camera Configuration |
| dcf | Arbortext Editor Document Type Configuration Data |
| dcf | CANopen Device Configuration Data |
| dcf | DynSite Configuration Data |
| dcf | HP 95LX Comm Program Settings Data |
| dcls | Catia V4 Settings |
| dcp | Adobe DNG Camera Profile |
| dcpr | Adobe DNG Camera Profile Recipe |
| dcst | Adobe InDesign Document Settings |
| def | Binary Editor Definition Data |
