| little | Mozilla Firefox Start-up Cache |
| liv | Living Actor Data File |
| livereg | Symantec Antivirus Session |
| liveupdate | Symantec LiveUpdate |
| lix | ExtendSim Simulation Software Library |
| ljb | LightJockey Database |
| lk | OpenInsight LK Data |
| lka | Lookout Direct Security Data |
| lkb | Faverly Data Recorder Data |
| lkp | Microsoft SMS Lookup File |
| lkt | EES Lookup Table |
| lkup | iiV Lookup |
| ll | List and Label Preview |
| ll3 | LapLink 3 Data |
| lla | PROJ.4 LLA Data |
| lld | Loan Level Disclosure Data |
| llge | Microsoft Windows Application Log |
| lli | Autodesk AutoCAD Landscape Library |
| llt | Liquidity Lighthouse Transaction Data |
| llv | Lizard Safeguard PDF Security License File |
| lm | ARPA-MIT Language Model File |
| lm3 | Bosphorus 3D Landmarking Database |
| lm4 | Steinberg LM-4 Program |
| lmat | LayaAir Material Data |
| lmb | LogoManager Backup File |
| lmc | Library Manager Database |
| lmd | Abbyy FineReader Morphological Model |
| lmf | Altera Library Mapping File |
| lmg | CryENGINE Locomotion Manager Group Animation |
| lmi | Homeportal SW1000 Firmware Recovery Data |
