| .FDT | Final Draft | Tekstitiedostot | Final Draft 5-7 Template | FormDocs | Interscape |
| .FF2 | AceBIT | Datatiedostot | Hello Engines! | Hello Engines | Interscape |
| .FFF | Hasselblad | Kameran Raakatiedostot | Hasselblad RAW Image | MAGGI | Interscape |
| .FIN | Interscape | Tekstitiedostot | Sapir Torah Text | Sapir Torah | Interscape |
| .FLAG | Interscape | Graafiset Tiedostot | FlagMaker Document | FlagMaker | Interscape |
| .FLEX | Unknown Developer | Datatiedostot | Flexi Data Smoothing File | Flexi Smoothing Data | Interscape |
| .FLUX | Interscape | Videotiedostot | FluxTime Studio Clip | FluxTime Studio | Interscape |
| .FMC | Interscape | Datatiedostot | FormConnect Form File | FormConnect | Interscape |
| .FMP | Dreamingsoft | Web-tiedostot | 123 Flash Menu Project | Profit Plan | Interscape |
| .FNO | Folio Corporation | Datatiedostot | Folio Infobase File | Atlast File Notes Organizer | Interscape |
| .FPG | The Game Creators | Pelitiedostot | FPS Creator Game Project File | FlameBird | Interscape |
| .FPK | Interscape | Pelitiedostot | Civilization 4 Data File | Take-Two Interactive Civilization 3 | Interscape |
| .FRD | Interscape | Datatiedostot | Frequency Response Data File | SPL Tracer | Interscape |
| .FSP | Wondershare Software Co., Ltd. | Datatiedostot | Flash Slideshow Builder Project | Fsplit | Interscape |
| .FUD | Interscape | Datatiedostot | FairUse Wizard Data File | FairUse Wizard | Interscape |
| .FUP | Interscape | Datatiedostot | FairUse Project File | FairUse Wizard | Interscape |
| .GAM | Nintendo | Pelitiedostot | Saved Game File | Dualis | Interscape |
| .GAME | Apple | Pelitiedostot | Apple Chess Saved Game | GameSalad Creator | Interscape |
| .GBF | Yuku | Tekstitiedostot | General Bible Format | Great Budget | Interscape |
| .GBX | Nadeo | Pelitiedostot | Nadeo Game File | Great Budget | Interscape |
| .GCF | Valve | Pelitiedostot | Game Cache File | Graphing Calculator | Interscape |
| .GCM | Nintendo | Pelitiedostot | GameCube ROM | WhineCube | Interscape |
| .GCT | Interscape | Pelitiedostot | Ocarina Cheat Code Manager Exported Cheat | Ocarina Cheat Code Manager | Interscape |
| .GDG | Interscape | Pelitiedostot | GDevelop Project File | GDevelop | Interscape |
| .GMD | YoYo Games | Sovelluskehittäjän tiedostot | Game Maker Program Code | Great Budget | Interscape |
| .GME | InterAct | Pelitiedostot | DexDrive Game Card File | PSXMemTool | Interscape |
| .GOLD | Interscape | Datatiedostot | Gnome Desktop Data | GNOME Desktop | Interscape |
| .GTP | Ucamco | Datatiedostot | Gerber Top Solder Paste Data File | GNOME Desktop | Interscape |
| .GZ | GNU Project | Pakatut tiedostot | Gnu Zipped Archive | Ark | Interscape |
| .H2O | Liquid Entertainment | Pelitiedostot | Battle Realms Game Data File | H2OMAP Water | Interscape |
| .HE0 | Humongous Entertainment | Pelitiedostot | Humongous Entertainment Game Archive | ScummVM | Interscape |
| .HGT | Safe Software | GIS-tiedostot | SRTM Elevation Data File | DG Terrain Viewer | Interscape |
| .HIS | Interscape | Tietokantatiedostot | FindinSite Database Definition File | PHDCC FindinSite-CD | Interscape |
| .HKL | Interscape | Datatiedostot | RMCProfile Range Of Values Data | RMCProfile | Interscape |
| .HNC | Interscape | Tekstitiedostot | NoteCenter Note | NoteCenter | Interscape |
| .HPK | Interscape | Pakatut tiedostot | HPack Compressed Archive | HPack | Interscape |
| .HPP | Microsoft Corporation | Sovelluskehittäjän tiedostot | C++ Header File | Haluha Pearls | Interscape |
| .HS | Open Source | Sovelluskehittäjän tiedostot | Haskell Script | RSD Lite | Interscape |
| .HSR | HS-Soft | Datatiedostot | RezeptAssist Exported Data | Hero Screen Recorder | Interscape |
| .HYP | Interscape | Pakatut tiedostot | HYPER Compressed Archive | Hyper | Interscape |
| .IDX | Unknown Developer | Harvinaiset Tiedostot | Movie Subtitle File | J2 Interactive MX Player | Interscape |
| .IFF | Electronic Arts | Äänitiedostot | Interchange File Format | IFFSnooper | Interscape |
| .IGR | Interscape | Äänitiedostot | Igor Engraver File | Igor Engraver | Interscape |
| .IMG | Unknown Developer | Levyn kuvatiedostot | Disk Image Data File | Diskcopy | Interscape |
| .INST | Interscape | Datatiedostot | RMCProfile Peak Profile Data | RMCProfile | Interscape |
| .IPS | ZeroSoft Zophar | Pelitiedostot | Internal Patching System Patch File | UIPS - Universal IPS Create/Apply Utility | Interscape |
| .IRX | Martin Stanek | Datatiedostot | Brewer Irradiation File | UVBrewer | Interscape |
| .ISH | Interscape | Pakatut tiedostot | ISH Compressed Archive | HiroRAR | Interscape |
| .ISO | Igor Pavlov | Levyn kuvatiedostot | Disc Image File | ISO Master | Interscape |
| .IVR | RealNetworks | Videotiedostot | Internet Video Recording | Zoom Plugin Viewer | Interscape |
| .KAP | Maptech | Datatiedostot | BSB Chart Image File | NOAA Chart Viewer | Interscape |
| .KRK | Interscape | Äänitiedostot | Karaoke Music File | JBK Karaoke Player | Interscape |
| .L2R | NCSoft | Pelitiedostot | Lineage II Replay File | NCSOFT Lineage II | Interscape |
| .LBU | Interscape | Asetustiedostot | Cloaked Affiliate Link Builder Settings File | Cloaked Affiliate Link Builder | Interscape |
| .LBXCOL | Libronix Corporation | eBook Tiedostot | Libronix DLS Resource Collection File | Logos Bible Software | Interscape |
| .LBXLLS | Interscape | Datatiedostot | Logos Libronix 3.0 Data | Logos Bible Software | Interscape |
| .LBXUPD | Interscape | Sovelluskehittäjän tiedostot | Libronix DLS Update Script | Logos Bible Software | Interscape |
| .LCB | Interscape | Varmuuskopiointitiedostot | Living Cookbook Backup File | Living Cookbook | Interscape |
| .LCT | Oracle Corporation | Tietokantatiedostot | Oracle Database Configuration File | Elsie | Interscape |
| .LEG | Interscape | CAD-tiedostot | LEGOCAD File | LEGOCAD | Interscape |
| .LEV | Interscape | Pelitiedostot | NetHack Level File | NetHack | Interscape |
| .LFL | LucasArts Entertainment Company, LLC | Pelitiedostot | LucasArts Games Resource File | ScummVM | Interscape |
| .LFM | Interscape | Datatiedostot | LifeForm Data | Life Form Studio | Interscape |
| .LIN | Autodesk, Inc. | CAD-tiedostot | AutoCAD Linetype File | X-Plane | Interscape |
| .LIX | Interscape | Datatiedostot | Logos Library System File | Logos Bible Software | Interscape |
| .LPJ | Interscape | Datatiedostot | LIMDEP Project | LIMDEP | Interscape |
| .LPT | Interscape | Datatiedostot | LogPlot Compiled Boring Log File | LogPlot | Interscape |
| .LRM | Microsoft Corporation | Datatiedostot | Encarta Class Server Learning Resource File | Line Rider 2: Unbound | Interscape |
| .LSF | Interscape | Datatiedostot | Logos Library System File | Logos Bible Software | Interscape |
| .LTX | GSC Game World | Pelitiedostot | S.T.A.L.K.E.R. Properties File | LaTeX Editor | Interscape |
| .LUB | Interscape | Datatiedostot | Lua Bytecode | LUA | Interscape |
| .LUC | SourceForge | Sovelluskehittäjän tiedostot | Compiled Lua Source File | LUA | Interscape |
| .MAE | Interscape | Pelitiedostot | My Avatar Editor Character File | My Avatar Editor | Interscape |
| .MAX | Autodesk, Inc. | 3D-kuvatiedostot | 3ds Max Scene File | PS2 Save Builder | Interscape |
| .MCH | Interscape | Asetustiedostot | Machinery HDR Effects | Machinery HDR | Interscape |
| .MCP | Freescale | Sovelluskehittäjän tiedostot | CodeWarrior Project | MegaCubo | Interscape |
| .MD | Various Developers | Sovelluskehittäjän tiedostot | Markdown Documentation File | PS2 Save Builder | Interscape |
| .MDX | Disc Soft Ltd. | Levyn kuvatiedostot | Extended Media Descriptor File | MDX Squisher | Interscape |
| .MFA | Clickteam | Sovelluskehittäjän tiedostot | Multimedia Fusion Development File | Multimedia Fusion | Interscape |
| .MFW | MamiyaLeaf | Kameran Raakatiedostot | Mamiya Camera Raw File | Multimedia Fusion | Interscape |
| .MGN | Interscape | Tietokantatiedostot | Modern Genealogy Database File | Modern Genealogy | Interscape |
| .MHP | Open Source | Datatiedostot | Maths Helper Plus File | MailShift | Interscape |
| .MHT | Various Developers | Web-tiedostot | MHTML Web Archive | WizBrother WizHtmlEditor | Interscape |
| .MHTM | Microsoft Corporation | Web-tiedostot | Mime HTML (MHTML) File | WizBrother WizHtmlEditor | Interscape |
| .MHTML | Microsoft Corporation | Web-tiedostot | Mime HTML (MHTML) File | WizBrother WizHtmlEditor | Interscape |
| .MII | Nintendo | Pelitiedostot | Wii Virtual Avatar File | My Avatar Editor | Interscape |
| .MIX | Microsoft Corporation | Rasterikuvatiedostot | Microsoft Image Exchange File | Command and Conquer | Interscape |
| .MK3D | Matroska | Videotiedostot | Matroska 3D Video File | MKVtoolnix | Interscape |
| .MKF | Interscape | Äänitiedostot | KaraBox Karaoke Music File | KaraBox | Interscape |
| .MKZ | Interscape | Varmuuskopiointitiedostot | PokerOffice Database Backup File | PokerOffice | Interscape |
| .MLA | Unknown Developer | Datatiedostot | WorshipCenter Pro Document | WorshipCenter Pro | Interscape |
| .MLS | KIDASA Software, Inc. | Datatiedostot | Milestones Simplicity File | WorshipCenter Pro | Interscape |
| .MMG | Moritz Bunkus | Asetustiedostot | MKVToolNix Muxing Settings | MKVtoolnix | Interscape |
| .MMX | Interscape | Pelitiedostot | Command And Conquer Game Data | Command and Conquer | Interscape |
| .MOOV | Apple | Videotiedostot | Apple QuickTime Movie | J2 Interactive MX Player | Interscape |
| .MOV | Apple | Videotiedostot | Apple QuickTime Movie | J2 Interactive MX Player | Interscape |
| .MPL | Sony | Videotiedostot | AVCHD Playlist File | J2 Interactive MX Player | Interscape |
| .MPO | CyberLink | Rasterikuvatiedostot | CIPA Multi Picture Object File | S3D Viewer | Interscape |
| .MRD | Interscape | Tekstitiedostot | MathRevolt Infinity Document | Infinity | Interscape |
| .MRP | Interscape | Datatiedostot | Infinity Solution Plot Data | Infinity | Interscape |
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