| lja | ljArchive Archive |
| lks | Liberkey Installation Package |
| lnx | Commodore 64 Lynx Archive |
| lok | WinGuard Pro Lok Archive |
| lou | Liquidware LouZip Archive |
| lpk | Lazarus Package |
| lpkg | Liferay Package |
| lqr | Squeezed LBR Archive |
| lrp | Linux Router Project Package |
| lrz | Long Range Zip Compressed Archive |
| lz | Lzip Compressed File |
| lz4 | LZ4 Compressed Data |
| lzg | LZG Compressed Data |
| lzh | LH ARC Archive |
| lzip | Lzip Compressed File |
| lzm | Slax Module |
| lzma | LZMA Compressed File |
| lzo | LZOP Compressed File |
| lzop | LZOP Compressed File |
| lzr | Crunched LBR Archive |
| lzw | LZW Compressed Amiga Archive |
| lzx | Amiga LZX Compressed Archive |
| m | Mathematica Package |
| maff | Mozilla Archive Format File |
| mb2 | McMyAdmin 2 Backup Archive |
| mbkp | Memeo Instant Backup Archive |
| mcaddon | Minecraft Addon Package |
| mcb | McMyAdmin Backup Archive |
| mcpack | Minecraft Resource Pack |
| mdbackup | iPhone Data Backup |
