| kws | KeyWallet Skin |
| kwt | BrailleNote KeyWord Text |
| kwu | KWUROHR Data |
| kwx | kCura Win Edds Export Data |
| kwx | Klusta Kwik Spiking Data |
| kwy | Keepaway Framework Learning Curve Data |
| kwz | Flipnote Studio 3D Flipnote Data |
| kxp | Key Home Gourmet Data File |
| kxw | Pedigree Central Database Index |
| kxy | SUPCRT92 K Values File |
| kyn | ALSee Thumbnail Cache |
| kyr | Lotus Domino Server Keyring |
| kzm | Karizma Designer Album |
| kzx | Kerkythea Zipped XML Material Data |
| l01 | EnCase Logical Evidence Data |
| l2l | IBM Voice Type Languages Addword Data |
| l4d | Maxon Cinema 4D Layout Data |
| l5e | VecTor5 Extended Load Output Data |
| l5k | RSLogix 5000 Project Export Data |
| l5r | VecTor5 Load Case Data |
| l5x | RSLogix 5000 XML Data |
| l64 | 64LAN Image |
| l6t | Line 6 POD HD500X Tone Data |
| la | Microth InPad Layout File |
| lab | MRMC Label Data |
| lab | Steinberg WaveLab CD/DVD Label Set |
| label | FreeSurfer Label |
| labels | Amira 3D Mesh Label Data |
| labx | Maestro Labor Analysis File |
| lac | Cognos Local Authentication Cache |
| lad | Daylon Leveller Animation |
| lae | IBM Cognos Local Authentication Export |
| laf | Essential Taceo License Activation File |
| lak | Kashmir 3D Lake Data |
| lanalyser | Novell Netware LANalyzer Trace Data |