| inc | Java Servlet Include |
| incr | Visual C# Compiler Incremental Data |
| inh | Visual Basic Basfwin Data |
| inn | Micro Focus COBOL Overlay File |
| ino | Arduino Sketch |
| inspxe | Intel Inspector Results Data |
| int | Delphi Interface Unit |
| int | Micro Focus COBOL Intermediate Code |
| 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 |
| ipnb | IPython Notebook Document |
| ipy | IPython Script |
| ipyn | IPython Notebook Document |
| ipynb | IPython Notebook Document |
| ipynd | IPython Notebook Document |
| ipynp | IPython Plot Document |
| irb | Interactive Ruby Script |
| ird | Crestron SIMPL IR Resource Data |
| irev | LiveCode RevServer Script |
| irobo | RoboMind Source Code |
| is | Modula-3 Intermediate Assembly File |
| is1 | Synergy/DE Data Index |
| isd | InstallShield Dialog |
| isl | InstallShield Pro Log |
| ism | Synergy/DE Data Index |
| isn | InstallShield Skin |
| iss | InstallShield Response File |
| itb | U-Boot uImage Image Tree Blob |
| itcl | Cygwin iwidgets Script |
| itf | JPI TopSpeed Pascal Interface File |
