| mfl | Localized Managed Object Format File |
| mfo | Perl ModInfo Descriptor |
| mfps | MFP Script |
| mft | Java Manifest File |
| mfu | MobileFrame Update Package |
| mfv | MobileFrame Device Pack |
| mfw | MobileFrame Workflow Pack |
| mfx | Multimedia Fusion Extension |
| min | Freemacs Mint Source Code |
| mingw | MinGW Makefile |
| miz | Mizar Article |
| mjs | ECMAScript JavaScript Module |
| mk | GNU Makefile |
| ml | OCaml Source Code |
| mlapp | MATLAB Application Package |
| mlb | FoxPro 2 for Macintosh Library |
| mlc | Message Tools for NetWare Source Code |
| mlh | Message Tools for NetWare Source Code |
| mli | OCaml Interface Source |
| mlib | MATLAB Shared Library |
| mlo | Beaglebone Prebootloader Image |
| mlua | MetaLua Source Code |
| mlv | LabVIEW Mathscript |
| mlw | WhyML Program |
| mly | OCaml Ocamlyacc Input Data |
| mmb | Oracle Forms Menu Module Binary |
| mmch | CodeWarrior Compiled HDR |
| mmk | MACSIMUS Metamake Data |
| mmo | WinDev HyperFileSQL Memo File |
| mmpa | MoreMotion Page |
| mmpf | CodeWarrior Preferences Data |
| mmt | Oracle Forms Menu Module Text |
| mmx | Oracle Forms Menu Module Executable |
| mn8 | SpaceMapper MN8 Script |
| mnft | Java Manifest File |