| jxl | TBC JobXML Data |
| jxt | Daqarta Juxt Data |
| jz | JamesZhu Browser Database |
| k | LS-DYNA Input Data |
| k01 | Clarion Database Keys |
| k03 | Clarion for DOS Database Key |
| k1 | DataFlex Index |
| k2 | DataFlex Index |
| k2p | Kryptel Encrypted Data |
| k3 | DataFlex Index |
| k4 | DataFlex Index |
| k5 | DataFlex Index |
| k6 | DataFlex Index |
| k7 | DataFlex Index |
| k7 | DCMO6 Emulator Tape Image |
| ka | Karma Assets Data |
| kab | Kmail Addressbook Data |
| kad | NI Kore Data |
| kal | Hondata KManager Calibration Data |
| kali | Kali Linux Related Data |
| kam | BEL Framework KAM Database |
| kan | Kwalitan Annotation Data |
| kbb | Jetico BestCrypt Key Block Backup |
| kbd | MountFocus Keyboard Designer Keyboard |
| kbk | Medeco XT Codebooks for Keys Data |
| kbp | Keirsey-Bates Temperament Sorter Profile Data |
| kbs | Keyboard Script |
| kbx | GnuPG Keybox File |
| kcd | Kayak Network Definitions Data |
| kcm | KonyvCalc Data |
| kco | Kwalitan Codes Data |
| kcs | Keep and Share Offline Calendar Data |
| kct | Knit Visualizer 1.0 Chart |
| kct | Kwalitan Categories Data |
| kd3 | Yayoi Kaikei Accounting Data |
