| .1ST | Microsoft Corporation | Tekstitiedostot | Visual FoxPro Documenting Wizard List | Microsoft Visual FoxPro | Microsoft Corporation |
| .3 | IBM | Tekstitiedostot | IBM Embedded ViaVoice Voice Type Languages Scripts Data | IBM Embedded ViaVoice | IBM |
| .3T | Global Publishing Solutions | Tekstitiedostot | Advent 3B2 Text File | Advanced Print Publisher (formerly Advent 3B2) | Global Publishing Solutions |
| .4 | IBM | Tekstitiedostot | IBM Voice Type Languages Scripts Data File | Mozilla Firefox | Mozilla |
| .4QR | 4D, Inc | Tekstitiedostot | 4th Dimension Database Windows Quick Report | 4D | 4D, Inc |
| .602 | Milan Broz | Tekstitiedostot | T602 Text File | T602VW | Milan Broz |
| .660 | Acresso Software, Inc. | Tekstitiedostot | FLEXnet Manager File | FLEXnet Manager | Flexera Software |
| .89T | Texas Instruments, Inc. | Tekstitiedostot | TI-89 Text File | TI Connect | Texas Instruments, Inc. |
| .9 | Ubisoft | Tekstitiedostot | Salt Lake Winter Olympics 2002 Game Music File | Salt Lake 2002 | Ubisoft |
| .9XT | Texas Instruments, Inc. | Tekstitiedostot | TI-89 Text File | TI Connect | Texas Instruments, Inc. |
| .A50 | Adobe Systems Incorporated | Tekstitiedostot | Adobe Authorware Library File | Adobe Authorware | Adobe Systems Incorporated |
| .ABW | Abisource | Tekstitiedostot | AbiWord Document | AbiWord | Open Source |
| .ACP | Alfresco Software, Inc. | Tekstitiedostot | Alfresco Content Package | Alfresco | Alfresco Software, Inc. |
| .ACT | Bell Labs | Tekstitiedostot | ADPCM Compressed Audio File | Unknown Software | Unknown Developer |
| .ADA | Open Source | Tekstitiedostot | Ada Source Code | Notepad++ | Don Ho |
| .ADW | Dr. K. Srinivasan | Tekstitiedostot | Adhawin Transliteration Scheme | Adhawin | Dr. K. Srinivasan |
| .AFF | Kingsoft | Tekstitiedostot | Spellcheck Dictionary Description File | Kingsoft Writer | Kingsoft |
| .AFT | Ancestry.com Inc. | Tekstitiedostot | Family Tree Database | Software MacKiev Family Tree Maker | Ancestry.com Inc. |
| .AGR | Ableton | Tekstitiedostot | Ableton Groove File | Ableton Live | Ableton |
| .AIM | AIMMS B.V. | Tekstitiedostot | AIMMS ASCII Model File | AIMMS | AIMMS B.V. |
| .AKS | Srinivas Annam | Tekstitiedostot | Aksharamala Keymap Source | Aksharamala | Interscape |
| .AKT | Srinivas Annam | Tekstitiedostot | Aksharamala Keymap Source | Aksharamala | Interscape |
| .ANS | Open Source | Tekstitiedostot | ANSI Text File | Microsoft Notepad | Microsoft Corporation |
| .APKG | Damien Elmes | Tekstitiedostot | Exported Anki Flashcard Deck | Anki | Damien Elmes |
| .APO | Abacre Limited | Tekstitiedostot | Abacre Paperless Office File | Abacre Paperless Office | Abacre Limited |
| .APRJ | Apache HTTP Project Management Committee | Tekstitiedostot | ApacheConf Project | Apache Web Server | Apache HTTP Project Management Committee |
| .APT | Apache Software Foundation | Tekstitiedostot | Almost Plain Text File | Apache OpenOffice | Apache Software Foundation |
| .ARK | Avanquest Software | Tekstitiedostot | PowerDesk Pro Archive | FreeArc | Bulat Ziganshin |
| .ASC | Symantec Corporation | Tekstitiedostot | PGP (Pretty Good Privacy) ASCII Armored File | Mozilla Thunderbird | Mozilla |
| .ASCII | Sublime HQ Pty Ltd | Tekstitiedostot | ASCII Text | Microsoft Notepad | Microsoft Corporation |
| .ASE | Adobe Systems Incorporated | Tekstitiedostot | Adobe Swatch Exchange File | Adobe Illustrator CC | Adobe Systems Incorporated |
| .ATY | G&A M.C. | Tekstitiedostot | Association Type Placeholder | Topicscape | G&A M.C. |
| .AW | Microsoft Corporation | Tekstitiedostot | Answer Wizard File | Microsoft Excel | Microsoft Corporation |
| .AWB | Nokia | Tekstitiedostot | AMR-WB Audio File | Apple QuickTime Player | Apple |
| .AWD | Microsoft Corporation | Tekstitiedostot | Microsoft Fax Document | PolyView | Polybytes |
| .AWH | ActiveWord Systems, Inc. | Tekstitiedostot | ActiveWords Browser Help File | ActiveWords | ActiveWord Systems, Inc. |
| .AWP | Ability Plus Software | Tekstitiedostot | Ability Write Template | Ability Office | Ability Plus Software |
| .AWT | Abisource | Tekstitiedostot | AbiWord Template | AbiWord | Open Source |
| .AWW | Ability Plus Software | Tekstitiedostot | Ability Write Document | Ability Office | Ability Plus Software |
| .AXR | Systems AXIS Ltd. | Tekstitiedostot | AXIS Diplomat Report | AXIS Diplomat | Systems AXIS Ltd. |
| .B4U | Open Source | Tekstitiedostot | Visual ReadMe Data File | docPointer | Open Source |
| .BAD | Microsoft Corporation | Tekstitiedostot | Exchange Badmail File | Microsoft Exchange Server | Microsoft Corporation |
| .BBE | MindGenius Ltd | Tekstitiedostot | Brainbloom Document Exchange File | MindGenius | MindGenius Ltd |
| .BBL | Thomas Feuerstack | Tekstitiedostot | BibTeX Generated Bibliography File | Bib2x | Alexander Feder |
| .BBS | Open Source | Tekstitiedostot | Bulletin Board System Text | Microsoft Notepad | Microsoft Corporation |
| .BDP | Microsoft Corporation | Tekstitiedostot | Exchange Diagnostic Message | Microsoft Exchange Server | Microsoft Corporation |
| .BDR | Microsoft Corporation | Tekstitiedostot | Exchange Non-Delivery Report Body File | Microsoft Exchange Server | Microsoft Corporation |
| .BDT | Don Ho | Tekstitiedostot | BDT Script | BDT-script | Don Ho |
| .BEAN | James Hoover | Tekstitiedostot | Bean Rich Text Document | Bean | James Hoover |
| .BEL | SourceForge | Tekstitiedostot | Beamer Layout File | Beamer | SourceForge |
| .BFX | Cheyenne Software (CYE) | Tekstitiedostot | Bitware Fax Document | FaxSee Pro | SFaxTools |
| .BGV | Bonanza Education | Tekstitiedostot | BonanzaGraf Financial Presentation | BonanzaGraf | Bonanza Education |
| .BIB | Oren Patashnik | Tekstitiedostot | BibTeX Bibliography Database | MacroMates TextMate | MacroMates |
| .BIBTEX | Oren Patashnik | Tekstitiedostot | BibTeX Bibliography Database | MacroMates TextMate | MacroMates |
| .BLL | LaserGraphics | Tekstitiedostot | Binary Lasergraphics Language Document | Lasergraphics WinRascol | LaserGraphics |
| .BLW | Adobe Systems Incorporated | Tekstitiedostot | Adobe Photoshop Black And White Presets File | Adobe Photoshop CC | Adobe Systems Incorporated |
| .BML | Various Developers | Tekstitiedostot | Bean Markup Language File | Microsoft Notepad | Microsoft Corporation |
| .BNK | Unknown Developer | Tekstitiedostot | Adlib Instrument Bank | Adlib Tracker II | Adlib Tracker II |
| .BNX | Open Source | Tekstitiedostot | Board Neutral Exchange File | Notepad++ | Don Ho |
| .BOP | Software Depot Online | Tekstitiedostot | Business Office Pro Document | Business Office Pro | Software Depot Online |
| .BPMN | KAISHA-Tec | Tekstitiedostot | Business Process Model And Notation Document | Avantage | KAISHA-Tec |
| .BPT | Corel | Tekstitiedostot | CorelDRAW Bitmap Master Data | CorelDRAW Graphics Suite | Corel |
| .BRH | Sheshadrivasu Chandrashekaran | Tekstitiedostot | Baraha Document File | Baraha | Baraha Software |
| .BRX | Qualcomm | Tekstitiedostot | BREW Application Resource File | Brew MP SDK | Qualcomm |
| .BTAB | Microsoft Corporation | Tekstitiedostot | Base Guitar Tabulature Data | Microsoft Notepad | Microsoft Corporation |
| .BTD | Biztree | Tekstitiedostot | Business-in-a-Box Document | Biztree Business-in-a-Box | Biztree |
| .BTX | SmartWare Corporation | Tekstitiedostot | SmartWare Backup Text File | SmartWare | SmartWare Corporation |
| .BXX | Bitmanagement Software | Tekstitiedostot | BS Contact Parameter File | Bitmanagement Software BS Contact | Bitmanagement Software |
| .BZABW | Abisource | Tekstitiedostot | Compressed AbiWord Document File | AbiWord | Open Source |
| .CAG | Microsoft Corporation | Tekstitiedostot | ClipArt Gallery Package | Microsoft PowerPoint | Microsoft Corporation |
| .CDS | CS Odessa | Tekstitiedostot | ConceptDraw SlideShow | ConceptDraw PRO | CS Odessa |
| .CHARSET | Sublime HQ Pty Ltd | Tekstitiedostot | Character Set | Apple TextEdit | Apple |
| .CHART | Interscape | Tekstitiedostot | Feedback Chart File | Microsoft Notepad | Microsoft Corporation |
| .CHORD | Open Source | Tekstitiedostot | Song Chords File | Notepad++ | Don Ho |
| .CLB | Microsoft Corporation | Tekstitiedostot | COM+ Catalog File | Microsoft COM+ | Microsoft Corporation |
| .COD | Unknown Developer | Tekstitiedostot | Compiled Source Code | Microsoft Visual Studio | Microsoft Corporation |
| .COMMON | Apple | Tekstitiedostot | Unix Script | Unix | AT&T Labs |
| .COO | Autodesk, Inc. | Tekstitiedostot | AutoCAD Bounding Coordinates Cookie | Microsoft Notepad | Microsoft Corporation |
| .CPR | Steinberg | Tekstitiedostot | Cubase Project | Steinberg Cubase | Steinberg |
| .CST | Smith Micro Software | Tekstitiedostot | Manga Studio Story File | Manga Studio | Smith Micro Software |
| .CTX | Microsoft Corporation | Tekstitiedostot | Visual Basic Control Binary File | Microsoft Visual Studio | Microsoft Corporation |
| .CWS | ChordWizard Software Pty Ltd | Tekstitiedostot | ChordWizard Songtrix Song | ChordWizard Songtrix | ChordWizard Software Pty Ltd |
| .CYI | Hot Neuron | Tekstitiedostot | Clustify Input File | Clustify | Hot Neuron |
| .CZS | Bruno DENIS | Tekstitiedostot | WinEcran Screen Link File | WinEcran | Bruno DENIS |
| .DCA | IBM | Tekstitiedostot | DisplayWrite Document | Advanced Computer Innovations WordPort | Interscape |
| .DCF | Sony Mobile Communications | Tekstitiedostot | DRM Content Format File | DRM Packager | Sony Mobile Communications |
| .DE | Interscape | Tekstitiedostot | DrawExpress Diagram File | DrawExpress | Interscape |
| .DESC | Electronic Arts | Tekstitiedostot | Battlefield 2 Map Description File | Battlefield 2 | Electronic Arts |
| .DFM | Open Source | Tekstitiedostot | Pascal File | Notepad++ | Don Ho |
| .DGS | TES | Tekstitiedostot | Dagesh Pro Document | TES Dagesh Pro | TES |
| .DH2 | Pursuit Software Ltd. | Tekstitiedostot | Report Viewer File | Pursuit CRM | Pursuit Software Ltd. |
| .DIZ | Unknown Developer | Tekstitiedostot | Description In Zip File | Microsoft Notepad | Microsoft Corporation |
| .DL | Microsoft Corporation | Tekstitiedostot | Zoo Tycoon 2 Data File | Zoo Tycoon 2 | Microsoft Corporation |
| .DNE | Norsys Software Corp | Tekstitiedostot | Netica Text File | Norsys Netica | Norsys Software Corp |
| .DOC | Microsoft Corporation | Tekstitiedostot | Microsoft Word Document (before The 2007 Version) | Apache OpenOffice | Apache Software Foundation |
| .DOCM | Microsoft Corporation | Tekstitiedostot | Word Open XML Macro-Enabled Document | Apache OpenOffice | Apache Software Foundation |
| .DOCS | Unknown Developer | Tekstitiedostot | Document | Unknown Software | Unknown Developer |
| .DOCX | Microsoft Corporation | Tekstitiedostot | Microsoft Word Open XML Document | LibreOffice | The Document Foundation |
| .DOCXML | Microsoft Corporation | Tekstitiedostot | Microsoft Word XML Document | Microsoft Word 2016 | Microsoft Corporation |
| .DOK | Nenad Hrg | Tekstitiedostot | DesktopOK Icons Layout File | DesktopOK | Nenad Hrg |
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