| i | OpenEdge ABL Include File |
| 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 |
| Modula-3 Intermediate Language Code |
| 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 |
| id1 | IDA Database |
| ida | Internet Data Administration Script |
| idapi | Borland Database Engine IDAPI Data |
| idb | IntelliJ IDEA Database |
| Pascal/Delphi Database |
| Visual Studio Intermediate Debug Data |
| idea | IntelliJ IDEA Metadata |
| identcache | Delphi Temporary Cache Data |
| RAD Studio Refactoring Data |
| ideplugin | Xcode IDE Plug-in |
| idh | OpenCBM File |
| idk | Interface Development Kit Archive |
| idl | Interface Definition File |
| OMG CORBA Interface Definition Language File |
| 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 |
| 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 |
| ihex | Intel HEX Format Data |
| ihp | Watcom C Compiler Help |
| ihx | Intel HEX Format Data |
| 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 |
| Euphoria Shrouded Source Code |
| Fortran 90 Inline Expansion Data |
| IL Source Code |
| MSIL Assembler Input Data |
| 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 |
