| gs | Gosu Class Data |
| gshader | Visual Studio GL Shader Data |
| gsoap | gSOAP Settings |
| gsp | Gosu Program |
| gsp | Groovy Server Page |
| gss | GAUSS Source Code |
| gst | Gosu Template |
| gsx | Gosu Enhancements Data |
| gsy | Green Shoes Package |
| gt | IBM WebSphere sMash Groovy Template |
| guess | Autotools Triplet |
| gui4cli | Gui4Cli Data |
| gum | GAMBIT Universal Model Machine Data |
| gwe | GameWeaver Executable |
| gwf | Benthic Golden Data File |
| gwsp | Axeda Builder Project |
| gxp | Google XML Pages File |
| gxr | GeneXus Report |
| gyd | Xilinx ISE CPLD Guide Data |
| gyp | Chromium GYP Language File |
| gypi | Chromium GYP Language Include |
| h | C Header File |
| h | Xcode Objective-C Header |
| h-- | Sphinx C-- Language Header File |
| h2 | H2 Database File |
| h32 | Borland C++ 32bit Include File |
| h86 | µVision Intel HEX Data |
| hac | Helma Actions Script |
| hai | NTgraph Nt09b-2b EMX Library |
| hal | HansaWorld Hansa Applications Language File |
| ham | HAM Executable File |
| haml | Haml Source Code |
| has | Haskell Script |
| hash | Crestron SIMPL Autoupdate Hash Data |
| hbb | HAHTsite HAHTtalk Basic Object Data |
| hbs | HAHTsite HAHTtalk Basic Code Page |
| hbs | Handlebars Template |
| hbw | HAHTsite Widget Source Code |
| hcf | Compact HAM Library |
| hdcl | Hierarchical Dynamic Composition Language Document |
| hdev | HDevelop Data |
| hdmp | Windows Heap Dump |
| hdvp | HDevelop External Procedure |
| hdx | Delphi MultiHelp Index |
| heh | Scarlett Expert System Compiler Facts Data |
| hei | Heitml Source Code |
| hen | HEN Project |
| het | WinSQL HTML Export Template |
| hex | Intel HEX Format Data |
| hg | GNOME C++ Header |
| hg | Mercurial Data |
| hgdeps | Mercurial Dependencies Data |
| hgignore | Mercurial Ignore Data |
| hgsigs | Mercurial Signatures Data |
| hgsub | Mercurial Subrepo Data |
| hgtags | Mercurial Tags Data |
| hh | HTML Help Header File |
| hhc | HTML Help Table of Contents |
| hhh | Power C Precompiled Header |
| hhk | HTML Help Index |
| hhl | Visual Basic Data |
| hi | Haskell Interface |
| hic | HicEst Script |
| hie | GHC HI Extended |
| hint | Visual C++ Hint Data |
| hiro | ARToolKit Hiro Marker Data |
| hj | Habanero-Java Source Code |
| hkk | HTML Help AutoIndex |
| hks | HTML-Kit Script |
| hl | Haxe Compiler Output |
| hla | High Level Assembly Source Code |
| hlsl | Microsoft DirectX D3D High Level Shader Language |
| hlsli | Microsoft DirectX D3D High Level Shader Language Include |
| hlx | Visual C++ Syntax Coloring Data |
| hm | WinHelp Context ID |
| hmp | 3D Gamestudio Terrain Data |
| hoc | HOC Script |
| hpack | Haskell Package |
| hpf | High Performance Fortran Source Code |
| hpp | C++ Header File |
| hprof | Eclipse IDE Java Heap Dump |
| hpw | CompuServe Home Page Wizard Document |
| hpy | Guppy-PE Profiler Data |
| hql | Apache Hive HiveQL Script |
| hrl | Erlang Header File |
| hs | Haskell Source |
| hsdl | Hierarchical Scan Description Language Data |
| hse | Homesite Snippet End |
| hshader | Visual Studio HShader Data |
| hsm | Assembly Header File |
| hsp | WinDev HyperFileSQL Stored Procedure |
| hss | Homesite Snippet Start |
| htd | Adobe ExtendScript HTML Document |
| htl | HTL Source |
| htp | htp Source File |
| hts | Uniface Server Page HTMs Data |
| hx | Haxe Source Code |
| hxa | MS Help 2 Project Attribute Definition |
| hxc | MS Help 2 Project Collection Definition |
| hxe | MS Help 2 Project Sample Definition |
| hxf | MS Help 2 Project Include File |
| hxk | MS Help 2 Project Index |
| hxml | Haxe Compiler Options |
| hxn | Microsoft Visual Studio Help Data |
| hxt | MS Help 2 Project ToC |
| hxv | MS Help 2 Project Virtual Topic Definition |
| hydra | Adobe Pixel Bender Kernel |
| hydra | Hydra Image Filter Program |
| hzo | CrossWorks for ARM Object |
| hzx | CrossWorks for ARM Linked Executable |
| i | APLAC Source Code |
| i | Borland C++ Intermediate Preprocessor Output |
| i | IAR System Preprocessed Source Data |
| i | INTERCAL Source File |
| i | OpenEdge ABL Include File |
| i | Visual C++ Preprocessed Source |
| i3 | Modula-3 Interface Source Code |
| i6 | Inform 6 Source Code |
| i64 | Interactive Disassembler Data |
| i6t | Inform 6 Template |
| i7 | Inform 7 Source Code |
| i7x | Inform 7 Extension Source Code |
| ian | COOL:Jex Business Team Model |
| iap | Infinity Engine Add-on Patcher File |
| ibl | IBasic Component |
| ibplugin | Interface Builder Plug-in |
| ib_mon | IncrediBuild Build Progress Data |
| ic | Esterel Intermediate Code |
| ic | µVision Intermediate C Source Code |
| icf | Implementation Configuration File |
| icfg | Aristotle Interprocedural Control Flow Graph |
| ici | ICI Source Code |
| icl | Clean Source Code |
| icp | Remote Call Profiler Data |
| icu | ICU Data |
| icz | Lib2Def Output File |
| id0 | IDA Database |
| ida | Internet Data Administration Script |
| idapi | Borland Database Engine IDAPI Data |
| idb | IntelliJ IDEA Database |
| idb | Pascal/Delphi Database |
| idb | Visual Studio Intermediate Debug Data |
| idea | IntelliJ IDEA Metadata |
| identcache | Delphi Temporary Cache Data |
| identcache | RAD Studio Refactoring Data |
| ideplugin | Xcode IDE Plug-in |
| idh | OpenCBM File |
| idk | Interface Development Kit Archive |
| idl | Interface Definition File |
| idl | OMG CORBA Interface Definition Language File |
| idl | Visual Studio C++ Interface Definition Library |
| idle | IDle Script Source |
| idll | CodeWarrior DLL |
| idml | Adobe InDesign Markup Language Document |
| idn | Alpha Five Index Definition File |
| idol | IDle Object Library |
| idt | Windows Installer Exported Database |
| idx | CA Visual Objects Project Index |
| idy | Micro Focus COBOL Debug Data |
| iex | Elixir Interactive Shell Script |
| ifm | FactoryTalk View Studio Information Message Component File |
| ifm | IBM WebSphere Interface Mapping |
| ifr | UEFI IFR Opcode |
| ifx | IBM Rational XDE IFX Data |
| ig | Modula-3 Generic Interface Source Code |
| igb | Intrinsic Alchemy Graphics Binary Data |
| igr | Quest3D Channel Group Layout Data |
| igz | Intrinsic Alchemy Asset |
| ih | C++ Internal Header |
| ihp | Watcom C Compiler Help |
| ii | GCC Preprocessed C++ Source Code |
| iim | iMacros Script |
| ijf | J Language Component File |
| ijl | J Locked Script |
| ijr | J Runtime Script |
| ijs | J Script File |
| ijt | J Language Labs File |
| ijx | J Language Execution Window Data |
| ik | Ioke Source Code |
| il | Cadence SKILL File |
| il | Euphoria Shrouded Source Code |
| il | Fortran 90 Inline Expansion Data |
| il | IL Source Code |
| il | MSIL Assembler Input Data |
| il | SimuPLC ECL Instruction List |
| ile | Encrypted Cadence SKILL File |
| ilk | Visual Studio Incremental Link File |
| ilv | ILOG Views Data |
| image | Squeak Image |
| imake | Imake File |
| img | Psion OPL Image |
| imgsao | Aleph One Image |
| iml | IntelliJ IDEA Module |
| imp | FileMaker Pro Import Data Filter |
| imp | Pascal/Delphi Implementation Data |
| in7 | Ox Data |
| ina | Alpha Five Form Definition Data |
| inc | ASP Include File |
| inc | General Include File |
| incr | Visual C# Compiler Incremental Data |
| index | Eclipse IDE Help Index |
| inh | Visual Basic Basfwin Data |
| inl | Visual C++ Inline Function File |
| inn | Micro Focus COBOL Overlay File |
| ino | Arduino Sketch |
| inspxe | Intel Inspector Results Data |
| int | Delphi Interface Unit |
| int | Micro Focus COBOL Intermediate Code |
| int | Visual FoxPro Codepage Data |
| into | Interspector Object |
| inventor | SGI Open Inventor Data |
| iobj | Visual Studio Intermediate Object |
| iot | Hitachi Ladder Editor IO Comment |
| ipb | Apple iOS Perl Script |
| ipch | Intellisense Precompiled Header |
| ipdb | Visual Studio Internal Compilation Database |
| ipdl | IPC Protocol Definition Language Document |
| ipp | Inline Guard Macro File |
| ipy | IPython Script |
| ipynb | IPython Notebook Document |
| ipynp | IPython Plot Document |
| ir | Crestron SIMPL IR Driver |
| irb | Interactive Ruby Script |
| ird | Crestron SIMPL IR Resource Data |
| ire | Ire Language Source Code |
| irev | LiveCode RevServer Script |
| irl | IBM WebSphere ILOG JRules Data |
| is | Modula-3 Intermediate Assembly File |
| is1 | Synergy/DE Data Index |
| isd | InstallShield Dialog |
| isl | InstallShield Pro Log |
| isn | InstallShield Skin |
| iss | InstallShield Response File |
| itb | U-Boot uImage Image Tree Blob |
| itcl | Cygwin iwidgets Script |
| itf | JPI TopSpeed Pascal Interface File |
| itq | SAIA S-Web ITQ File |
| itrace | Microsoft Visual Studio iTrace Data |
| its | U-Boot uImage Image Tree Source |
| ivu | ImmerVision XML User Interface |
| ivy2 | Apache Ivy 2 Cache |
| iwb | IWBasic Source Code |
| iwdgt | iWeb Widget |
| iws | IntelliJ IDEA Workspace |
| ix3 | Instant.Exe 3.0 Script |
| ixx | Modula-3 Linker Information Data |
| izd | Intrexx Application Export Format Data |
| izs | 1st Page 2000 Script |
| i_caf | Amazon Lumberyard Intermediate CAF Data |
| j1 | EDIT Compiler JEDEC Boundary Data |