| cx | Codemapper Script |
| cxx | C++ Source Code |
| d | D Source Code |
| d | GCC Dependency File |
| d4 | Dataphor Source Code |
| d4c | Dataphor Catalog Data |
| da | Gcov Data File |
| dabriefcase | RemObjects Data Abstract File Briefcase |
| daconfig | RemObjects Data Abstract Configuration |
| dad | RemObjects Delphi Data Abstract Driver |
| dart | Dart Source Code |
| dbag | WinSQL DataBag Data |
| dbg | Microsoft Visual Studio Debug File |
| dbgdt | IAR System Debugger Desktop Data |
| dbi | Data Explorer Information |
| dblink | Altium Designer Database Link |
| dblog | Debugview++ Debug Log |
| dbml | Database Markup Language File |
| dbo | DarkBASIC Object |
| dbp | Visual Studio Database Project |
| dbproj | Visual Studio 2010 Database Project |
| dcf | ProWorx NXT Database Configuration |
| dci | RAD Studio Delphi Code Insight |
| dcp | Delphi Component Package |
| dcr | Delphi Component Resource |
| dct | Delphi Component Template |
| dcu | Delphi Compiled Unit |
| dcuil | Delphi .NET Compiled Unit |
| dda | GLBasic ASCII Scene Data |
| ddb | ProWorx NXT Descriptor Data with Blocking |
