| 31. | .mar | Archive (Microstation) ◊ Assembly program (VAX Macro) ◊ Report shortcut (Microsoft Access) |
| 32. | .marm | Makefile for MARM platform (EPOC) |
| 33. | .mas | Smartmaster set (Freelance Graphics) |
| 34. | .mass | Text document (Mass 11) |
| 35. | .mat | Matrix data file (Matlab) ◊ Table shortcut (Microsoft Access) ◊ geocoding matching parameters file (ArcView) |
| 36. | .maud | Sample format (Maud) |
| 37. | .max | Document (Paperport) ◊ Layout file (OrCad) ◊ Max language source code file ◊ Scene (3D Studio Max) |
| 38. | .maz | Data (dVS/dVISE) ◊ Game data (Hover maze) |
| 39. | .mb | Binary file (bitmaps etc.) (Mathematica) ◊ Memo field values for database (Paradox) |
| 40. | .mb1 | Game data (Apogee Monster Bash) |