| xbckl | ApSIC Xbench Checklist Data |
| xbd | JAXB Schema Data |
| xbd | Xilinx Board Description Format Data |
| xbdr | Darkroom Booth Template |
| xbf | XAML Binary File |
| xbin | RegSupreme Pro Licence Data |
| xbn | Xnick Nick Backup Data |
| xbpkg | ApSIC Xbench Package |
| xbs | XnView Script |
| xc0 | XTreeGold for Dos Help Data |
| xc3 | Cast3D 3D Scene Data |
| xcbr | Sonic Workbench XPath Routing Rules |
| xcc | Fiery Color Profiler Locked Profile |
| xccdf | Extensible Configuration Checklist Description Format Data |
| xccolortheme | Xcode Color Theme Data |
| xcd | WarpIN Data File |
| xcesession | PDFXEdit Session Data |
| xci | Switch Gamecard Dump Image |
| xcl | XTree for Windows Script |
| xclpack | PDFXEdit UI Language Pack |
| xcn | GenePattern XCN Data |
| xco | Xilinx CORE Generator Log |
| xcorpus | Xaira Corpora Data |
| xcos | Scilab Xcos Data |
| xcp | Casio ClassPad 300 Exported ClassPad |
| xcs | TBX eXtensible Constraint Specification |
| xcsl | CineStyle Color Correction Data |
| xcsr | Oracle UCM Content Folio XML |
| xcst | Oracle UCM Content Folio Template |
| xct | ExtremeCopy Task |
