| .NLS | Uri Wilensky | Pliki systemowe | NetLogo Source Code File | MacroMates TextMate | MacroMates |
| .NT | Microsoft Corporation | Pliki systemowe | Windows NT Startup File | Microsoft Windows | Microsoft Corporation |
| .NU6 | Symantec Corporation | Pliki systemowe | Norton Utilities System DLL File | Norton Utilities | Symantec Corporation |
| .NXS | Unknown Developer | Pliki systemowe | AdaOS Support Module | Unknown Software | Unknown Developer |
| .ODR | Open Source | Pliki systemowe | OpenIV Model Data | OpenIV | Open Source |
| .OSC | OpenStreetMap | Pliki systemowe | OpenStreetMap Change File | Merkaartor | Bart Vanhauwaert, Chris Browet, Ladislav Láska, and others |
| .OTE | FTP Software | Pliki systemowe | TNVTPlus Teach Mode Script File | TNVTPlus | FTP Software |
| .OV3 | Microsoft Corporation | Pliki systemowe | DOS Overlay File | MS-DOS | Microsoft Corporation |
| .P5X | Microsoft Corporation | Pliki systemowe | Microsoft Windows System Data | Microsoft Windows | Microsoft Corporation |
| .PANIC | Open Source | Pliki systemowe | Kernel Panic File | Notepad++ | Don Ho |
| .PAT | Autodesk, Inc. | Pliki systemowe | AutoCAD Hatch Pattern File | Autodesk AutoCAD | Autodesk, Inc. |
| .PBD | EaseUS | Pliki systemowe | EaseUS Todo Backup Backup File | EaseUS Todo Backup | EaseUS |
| .PCF | Blackstrip Studios | Pliki systemowe | PaintCAD Font | PaintCAD | Blackstrip Studios |
| .PCI | Microsoft Corporation | Pliki systemowe | PCI Miniport Data | Microsoft Windows | Microsoft Corporation |
| .PCK | Microsoft Corporation | Pliki systemowe | System Center Configuration Manager Package File | Microsoft system center configuration manager | Microsoft Corporation |
| .PD0 | SonTek | Pliki systemowe | SonTek Firmware File | Unknown Software | Unknown Developer |
| .PDL | PDL Developerment Team | Pliki systemowe | Perl Data Language File | perldl | Open Source |
| .PDR | Microsoft Corporation | Pliki systemowe | Windows Port Driver | Windows Control Panel | Microsoft Corporation |
| .PFX | Various Developers | Pliki systemowe | PKCS #12 Certificate File | Adobe Acrobat DC | Adobe Systems Incorporated |
| .PIT | Samsung Electronics | Pliki systemowe | Samsung Phone Firmware File | Google Android | Google |
| .PLK | Advanced Micro Devices, Inc. | Pliki systemowe | AMD ATI Radeon Video Driver | ATI Multimedia Center | Advanced Micro Devices, Inc. |
| .PNF | Microsoft Corporation | Pliki systemowe | Precompiled INF File | Microsoft Windows | Microsoft Corporation |
| .POL | Microsoft Corporation | Pliki systemowe | Windows Policy File | Registry.Pol Viewer Utility | SDM Software |
| .PPD | Adobe Systems Incorporated | Pliki systemowe | PostScript Printer Description File | Adobe PageMaker | Adobe Systems Incorporated |
| .PPM | The GIMP Development Team | Pliki systemowe | Portable Pixmap Image File | Adobe Photoshop | Adobe Systems Incorporated |
| .PRD | SoftMaker Software | Pliki systemowe | SoftMaker Presentations Document | Softmaker Office | SoftMaker Software |
| .PREFPANE | Apple | Pliki systemowe | Mac OS X System Preference Pane | Apple OS X | Apple |
| .PRF | Microsoft Corporation | Pliki systemowe | Outlook Profile File | Microsoft Outlook 2016 | Microsoft Corporation |
| .PRINTEREXPORT | Microsoft Corporation | Pliki systemowe | Windows Printer Migration File | Microsoft Windows 7 | Microsoft Corporation |
| .PROFILE | GNU Operating System | Pliki systemowe | Bash Shell Profile | MacroMates TextMate | MacroMates |
| .PROP | Google | Pliki systemowe | Android Build Properties File | Google Android | Google |
| .PRS | Software Publishing Corporation (SPC) | Pliki systemowe | Harvard Graphics Presentation | Corel Presentations X8 | Corel |
| .PRT | PTC | Pliki systemowe | Pro/ENGINEER Part File | Autodesk Fusion 360 | Autodesk, Inc. |
| .PS2 | Datel | Pliki systemowe | Sharkport Saved Game File | PS2 Save Builder | Interscape |
| .PSSC | Microsoft Corporation | Pliki systemowe | Windows PowerShell Session Configuration File | Microsoft Windows | Microsoft Corporation |
| .PWL | Microsoft Corporation | Pliki systemowe | Windows Password List | Proactive System Password Recovery | ElcomSoft |
| .PXE | Open Source | Pliki systemowe | Linux, Unix Network Bootable Image | Linux | Open Source |
| .QCC | Niobrara R&D Corporation | Pliki systemowe | NIOBRARA QUCM Firmware File | Unknown Software | Unknown Developer |
| .QPR | Microsoft Corporation | Pliki systemowe | FoxPro Generated Query Program | Microsoft Visual FoxPro | Microsoft Corporation |
| .QTS | Apple | Pliki systemowe | QuickTime System File | Apple QuickTime Player | Apple |
| .QVM | Open Source | Pliki systemowe | Q Virtual Machine | Q (emulator) | Open Source |
| .RAT | World Wide Web Consortium (W3C) | Pliki systemowe | PICS Rating File | Microsoft Notepad | Microsoft Corporation |
| .RBH | RBH Access | Pliki systemowe | RBH Access Technologies Firmware | Unknown Software | Unknown Developer |
| .RC2 | Microsoft Corporation | Pliki systemowe | Visual Studio Resources File | Microsoft Visual Studio | Microsoft Corporation |
| .RCO | Sony | Pliki systemowe | PlayStation Portable File | RCO Editor | Open Source |
| .RDZ | Mandriva S.A. | Pliki systemowe | Mandrake Linux Install File | Mandriva Linux One | Mandriva S.A. |
| .REG | Microsoft Corporation | Pliki systemowe | Registry File | Windows Registry Editor | Microsoft Corporation |
| .RESTORELIST | Microsoft Corporation | Pliki systemowe | Microsoft Windows File System Permission | Microsoft Windows | Microsoft Corporation |
| .RIO | IBM | Pliki systemowe | IBM AIX System Data | IBM AIX | IBM |
| .RMT | The Catalina Group | Pliki systemowe | Router Firmware File | Internet Explorer | Microsoft Corporation |
| .RPP | Cockos Incorporated | Pliki systemowe | REAPER Project | REAPER | Cockos Incorporated |
| .RQF | R-Quest Technologies | Pliki systemowe | R-Quest Duplication Systems Firmware Update File | TrueNet | R-Quest Technologies |
| .RUF | Samsung Electronics | Pliki systemowe | Samsung DVD And Blu-ray Player Firmware File | Windows Built-in USB Drive Software | Microsoft Corporation |
| .RVP | Sharp Electronics | Pliki systemowe | Sharp Blu-ray Player Firmware File | Unknown Software | Unknown Developer |
| .RX | Microsoft Corporation | Pliki systemowe | MS-DOS 7 Data | Microsoft Windows | Microsoft Corporation |
| .SAVER | Apple | Pliki systemowe | Mac OS X Screen Saver | Apple OS X | Apple |
| .SB | MIT Media Lab | Pliki systemowe | Scratch Project File | MIT Scratch | MIT Media Lab |
| .SBF | Google | Pliki systemowe | Android System File | Google Android | Google |
| .SBN | ESRI | Pliki systemowe | ESRI Spatial Binary File | ESRI ArcGIS for Desktop | ESRI (Environmental Systems Research Institute) |
| .SCF | Microsoft Corporation | Pliki systemowe | Windows Explorer Command | Microsoft Windows | Microsoft Corporation |
| .SCHEMAS | Open Source | Pliki systemowe | GConf Schema Definition File | GNU Emacs | GNU Project |
| .SCR | Microsoft Corporation | Pliki systemowe | Windows Screensaver File | Microsoft Windows | Microsoft Corporation |
| .SCRIPT | Unknown Developer | Pliki systemowe | Generic Script File | LibreOffice | The Document Foundation |
| .SDG | Golden Software LLC | Pliki systemowe | Strater Project File | Strater | Golden Software LLC |
| .SDT | Intuit, Inc. | Pliki systemowe | QuickBooks Data File | Intuit QuickBooks Pro | Intuit, Inc. |
| .SERVICE | Lennart Poettering and Kay Sievers | Pliki systemowe | Systemd Service File | Linux | Open Source |
| .SF | Institut de Recherche et de Coordination Acoustique/Musique (IRCAM) | Pliki systemowe | IRCAM Sound File | Awave Studio | FMJ-Software |
| .SF0 | Microsoft Corporation | Pliki systemowe | Windows Sytem File Check File | Microsoft Windows | Microsoft Corporation |
| .SFCACHE | Microsoft Corporation | Pliki systemowe | ReadyBoost Cache File | Microsoft Windows | Microsoft Corporation |
| .SFE | Unknown Developer | Pliki systemowe | Logomatic V2 Firmware | Unknown Software | Unknown Developer |
| .SHA | Corel | Pliki systemowe | CorelDraw Shader File | CorelDRAW Graphics Suite | Corel |
| .SHD | Microsoft Corporation | Pliki systemowe | Windows Print Job Shadow File | Microsoft Windows | Microsoft Corporation |
| .SHS | Microsoft Corporation | Pliki systemowe | Microsoft Scrap File | Microsoft Excel | Microsoft Corporation |
| .SID | Valve | Pliki systemowe | Steam Game Data Backup File | Steam | Valve |
| .SIN | Big Huge Games | Pliki systemowe | Rise Of Nations Campaign Media File | Rise Of Nations | Big Huge Games |
| .SL | SourceForge | Pliki systemowe | Unix Software License File | Vi | SourceForge |
| .SPARC | Skype Technologies | Pliki systemowe | Skype Plugin Archive | Skype | Skype Technologies |
| .SPL | Microsoft Corporation | Pliki systemowe | Windows Print Spool File | Microsoft Windows | Microsoft Corporation |
| .SQM | Microsoft Corporation | Pliki systemowe | Service Quality Monitoring File | Microsoft Windows | Microsoft Corporation |
| .SREC | Motorola | Pliki systemowe | Motorola S-record Data | SRecord | Open Source |
| .STR | dBase, LLC | Pliki systemowe | dBASE Structure List Object File | dBase | dBase, LLC |
| .STY | Jørgen Sørensen / Jososoft | Pliki systemowe | Yamaha/Korg Keyboard Style | Style Fixer | Jørgen Sørensen / Jososoft |
| .SWAP | Microsoft Corporation | Pliki systemowe | Swap File | Microsoft Windows | Microsoft Corporation |
| .SWP | Microsoft Corporation | Pliki systemowe | Swap File | Microsoft Windows | Microsoft Corporation |
| .SYS | Microsoft Corporation | Pliki systemowe | Windows System File | Microsoft Windows | Microsoft Corporation |
| .TBR | Adobe Systems Incorporated | Pliki systemowe | Adobe Photoshop Custom Toolbar Preset | Adobe Photoshop | Adobe Systems Incorporated |
| .THEME | Microsoft Corporation | Pliki systemowe | Microsoft Plus! Desktop Theme | Microsoft Windows | Microsoft Corporation |
| .TNC | Texas Instruments, Inc. | Pliki systemowe | Texas Instruments TI-Nspire CAS OS Image | TI-Nspire Student Software | Texas Instruments, Inc. |
| .TOS | Atari Corporation | Pliki systemowe | Atari ST TOS Archive File | The Operating System (TOS) | Atari Corporation |
| .UBL | Texas Instruments, Inc. | Pliki systemowe | DM35x User Boot Loader Data | DM35x, | Texas Instruments, Inc. |
| .UCE | Microsoft Corporation | Pliki systemowe | Windows UCE System File | Microsoft Windows | Microsoft Corporation |
| .UPD | Various Developers | Pliki systemowe | Program Update Information | Microsoft Notepad | Microsoft Corporation |
| .UX | AT&T Labs | Pliki systemowe | Unix File | Unix | AT&T Labs |
| .UXZ | IBM | Pliki systemowe | IBM Flex CMM Update Data | CMM Firmware | IBM |
| .VAP | Dialogic | Pliki systemowe | Dialogic Indexed Voice Audio File | Syntellect VoiceXML Studio | Syntellect |
| .VCE | Avanset | Pliki systemowe | Visual CertExam Suite Exam File | Visual CertExam Suite | Avanset |
| .VDX | Microsoft Corporation | Pliki systemowe | Visio Drawing XML File | OmniGraffle | The Omni Group |
| .VET | Lectra | Pliki systemowe | Lectra Cutter's Must File | Modaris | Lectra |
| .VFS | Unknown Developer | Pliki systemowe | Virtual File System Index | GnomeVFS | GNOME |
| .VGA | Microsoft Corporation | Pliki systemowe | VGA Display Driver | Microsoft Windows | Microsoft Corporation |
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