| cgi | RAD Studio CodeGuard Configuration |
| cginc | Unity Custom Shader Include |
| cgl | RAD Studio CodeGuard Log |
| cgr | Quest3D Channel Group File |
| cgt | GOLD Parser Compiled Grammar Table |
| cgvp | Nvidia Cg Toolkit XML Data |
| cham | Compiled HAM |
| changes | Squeak Changes Data |
| chef | Chef Source Code |
| chh | Borland C++ Header |
| chi | C To Haskell Interface File |
| chr | Amazon Lumberyard Character Asset Data |
| chs | Haskell Source With C Hooks |
| cic | Hitachi Ladder Editor Circuit Comment |
| ciq | CONNX InfoNaut Query |
| cjs | CommonJS Script |
| ck | ChucK Source Code |
| ckbx | Cricket Audio XML Bank Description |
| ckg | Kokogut C Output File |
| ckm | Creation Kit Macro |
| cko | Kokogut C Output File |
| ckp | Microsoft SQL Server Checkpoint Data |
| cl | Lisp Source Code |
| cl | OpenCL Kernel |
| classpath | Eclipse IDE JAVA Project Classpath Data |
| clb | Code Librarian Database |
| clips | Coda Clips Data |
| clj | Clojure Source Code |
| cljc | Clojure Macros Code |
| cljs | ClojureScript Source Code |
