| logic | Logic Pro Project |
| logicx | Logic Pro X Project |
| logoist | Logoist Project |
| logx | VMware Workbench Log Browser Project |
| loxone | Loxone Config Project |
| lpj | LIMDEP Project |
| lpp | CyberLink LabelPrint Project |
| Lets Photo Express Project |
| lpu | SDL Passolo Localization Project |
| ls3 | Lumion Project |
| ls3proj | Microsoft Visual Studio LightSwitch Project |
| ls4 | Lumion Project |
| ls5 | Lumion Project |
| ls6 | Lumion Project |
| ls7 | Lumion v7 Project |
| lse | PointCab Laser Scanning Project |
| lso | Logic Audio Project |
| lsproj | Faro SCENE Laser Scanner Project |
| Lens Studio Project |
| Livestream Studio Project |
| LoiLoScope Project |
| Microsoft Visual Studio LightSwitch Project |
| lsxproj | Microsoft Visual Studio 2013 LightSwitch Project |
| lsxtproj | Microsoft Visual Studio LightSwitch Project |
| ltp | Silk Performer Project |
| lts | Labelled Transition System Analyser Project |
| ltw | IncrediMail Letter Creator Project |
| lun | DB-MAIN Project |
| lut | Lutron RadioRA 2 Project Database |
| lutx | Lutron RadioRA 2 Project Database |
| lv1 | LiVES Clip Backup |
| lv2 | LiVES Project |
| lvproj | LabVIEW Project |
| lvprojx | LabVIEW Web UI Project |
| lvrbt | LabVIEW NXT Robot Project |
| lvu | Livid Union Project |
| lxsopt | Liquid XML Studio Project Options |
| lxsproj | Liquid XML Studio Project |
| m2j | Moldex3D Shell Project |
| m2k | MAXQDA 1 Project |
| m3j | Moldex3D Solid Project |
| m7p | Multilizer Project File |
| magics | Magics Project |
| mani | Mine-imator Animation Project |
| mapf | MainActor Project |
| mbd | Medbasin Project |
| Multimedia Builder Project |
| mblock | mBlock Project |
| mbp | CyberLink MediaShow Project |
| Medbasin Project |
| mbpav | microBasic Pro for AVR Project |
| mbppi | microBasic Pro for PIC Project |
| mcf | CEWE Creator Photobook Project |
| mcp | CodeWarrior Project |
| MPLAB IDE Project |
| mcpav | microC for AVR Project |
| mcpj | PlayMemories Project |
| mcppi | microC for PIC Project |
| mcs | Mimics Project |
| mcsp | My Craft Studio Project |
| mcsx | My Craft Studio Professional Project |
| mcw | Macaw Project |
| md8 | GarageCUBE Modul8 Project |
| Mediator 8 Project |
| mdj | StarUML Project File |
| mdr | MagicDraw Project |
| mds | TestComplete Project |
| mdsp | MinGW Developer Studio Project |
| mdtp | MDT3 Tool Project |
| mdxml | MagicDraw UML Project |
| mdzip | MagicDraw Project Archive |
| me3 | Arcsoft MultiMedia Email 3.0 Project |
| med | RSView Development Project |
| mep | Movavi Video Editor Project |
| mepb | Movavi Video Editor Project |
| mepj | Movavi Video Editor Plus Project |
| mepx | Movavi Video Editor Project |
| merlin2 | Merlin Project |
| mfg | MediaForge Runtime Project |
| mfp | MediaFACE Project |
