| xgm | Exient XGS Model Data |
| xgr | GraphEdit Filter Graph Markup Language |
| xgt | Exient XGS Texture Data |
| xib | Apple Interface Builder Development-Time Resources |
| xil | Xilize Markup Source |
| xilinc | Xilize Include |
| xilize | Xilize Configuration Data |
| xin | OmniMark Include File |
| xiw | CSR µEnergy SDK Workspace |
| xje | XJEase Source Code |
| xl | XBLite Source Code |
| xlc | Exient XGS Locale Data |
| xlist | MASM XLIST Data |
| xmat | Exient XGS Shader Material Data |
| xmcf | FileMaker Pro Custom Function Data |
| xmla | XML for Analysis File |
| xmlc | ASP.NET Compiled XML |
| xmljet | Eclipse JET XML Template |
| xmlo | FileMaker Pro Layout Object Data |
| xmta | Visual Studio Design-Time Attribute Data |
| xn | Cygwin LD-Script Data |
| xnb | XNA Game Studio Binary Package |
| xnd | exNode Download Data |
| xob | WeintekHMI EasyBuilder 8000 XOB File |
| xojo_binary_menu | Xojo Binary Menu Data |
| xojo_binary_project | Xojo Binary Project |
| xojo_binary_toolbar | Xojo Binary Toolbar Data |
| xojo_binary_window | Xojo Binary Window Data |
| xojo_menu | Xojo Menu Data |
| xojo_project | Xojo Project |