| Extension | 描述 | 檔案格式 |
|---|
| laccdb | Microsoft Access Lock File | 資料檔 |
| lang | Skype Language File | 設定檔 |
| lay | Rhinoceros Layer File | 3D Files |
| lbl | dBase Label File | 資料檔 |
| lcd | CDSpace disk image File | 磁碟映像檔 |
| lck | Lock File | Misc Files |
| lcs | L0phtCrack Audit File | Misc Files |
| ldb | Microsoft Access Lock File | Misc Files |
| ldf | Server Transaction Log File | 資料檔 |
| ldif | LDAP Data Interchange Format File | 資料檔 |
| ldw | Virtual Villagers Data File | 遊戲檔案 |
| lex | Adobe Proximity Dictionary File | Misc Files |
| lex | Microsoft Office Custom Dictionary Files | Misc Files |
| lex | LEX File | Misc Files |
| lib | AS/400 Library File | 資料檔 |
| lic | Licence File | 設定檔 |
| lid | Kodak Gallery Album File | 圖檔 |
| list | BlindWrite Copier File | 磁碟映像檔 |
| lit | eBook File | 文字檔 |
| lml | Nokia PC Suite Log File | Misc Files |
| lmp | Lump File | 遊戲檔案 |
| lng | Adobe Acrobat Language Plugin File | Plugin Files |
| lnk | Windows Shortcut File | 系統檔案 |
| loc | MicroSim Report File | 文字檔 |
| lock | Net Framework Lock File | 資料檔 |
| log | Log File | 文字檔 |
| lrc | Lyric File | 文字檔 |
| lrf | Microsoft C/C++ Linker Response File | Developer Files |
| lst | Data List File | 文字檔 |
| ltc | LTC Saved Analysis File | 文字檔 |
| ltx | LaTeX Document | 文件檔案 |
| lua | Lua Source Code File | Developer Files |
| lvl | Game Level File | 遊戲檔案 |
| lwp | IBM Word Pro Document File | 文件檔案 |
| lzc | Need For Speed Game Data File | 遊戲檔案 |
| lzh | Compressed Archive File | 壓縮檔案 |