| nga | Xilinx ISE NetGen Data |
| ngi | NGI Package |
| ngo | Norton Guide Linker Object |
| Xilinx ISE Logical Description Data |
| nhs | NHibernate Settings File |
| ni | NetObjects Fusion Preview |
| nib | Apple Interface Builder Resources |
| nim | Nim Source Code |
| Nimrod Source Code |
| nimble | Nimble Package Data |
| nir | AdminStudio Repackaging Wizard Output |
| nj | Nunjucks Template |
| njk | Nunjucks Template |
| njp | njPipes Compiler Data |
| njs | Nunjucks Template |
| nk | NUKE Script |
| nkple | Nuke Personal Learning Edition Script |
| nky | Xilinx ISE BitGen Key Data |
| nlf | Xilinx ISE NetGen Log |
| nls | NetLogo Source Code |
| nmc | Xilinx ISE Physical Macro Library |
| nmf | Native Client Manifest File |
| nmk | NMake Makefile |
| nml | NML Language Source Code |
| nms | Numega SoftICE Loader Data |
| nod | NetObjects Fusion Site File |
| node | Node.js Binary Addon |
| nokogiri | Nokogiri Source Code |
| noq | NOQ Source Code |
| npi | dBase Application Generator Source Code |
| npmignore | NPM Ignore |
| nqc | Not Quite C Source Code |
| nqp | Visual Studio Code Data |
| nsb | NS Basic/CE Data |
| nse | Nmap Scripting Engine Script |
| nsh | NSIS Header |
| nsi | NSIS Script File |
| nsis | NSIS Script File |
| nsl | nsL Script |
| nuke | NUKE Script |
| nunj | Nunjucks Template |
| nunjs | Nunjucks Template |
| nunjucks | Nunjucks Template |
| nupkg | NuGet Package |
| nuspec | NuGet Specification Data |
| nut | Squirrel Source Code |
| nvb | NVSG SDK Scene Graph |
| nvv | Nvidia Vertex Shader Profile |
| nw | NW.js App Package |
| Sweave Document |
| nxb | C4 Engine Binary Model Data |
| nxc | Not eXactly C Source Code |
| nxd | AdaOS Debugging Information |
| nxe | AdaOS Main Program Module |
| nxg | eSite Builder NXG Web Page |
| nxp | AdaOS Profiling Information |
| nxs | AdaOS Support Module |
| nxu | C4 Engine XML Model Data |
| o | Compiled Object File |
| o1 | Free Pascal Object File for GO321v1 Platform |
| oat | Android Compiled OAT |
| ob2 | Oberon 2 Source Code |
| obak | WinSQL Offline Backup Data |
| obe | Objeck Executable File |
| obh | Hitachi Ladder Editor Object Program |
| obj | Compiled Object File |
| Intel Relocatable Object Module |
| Visual Studio Compiled Object |
| obl | Objeck Compiled Library |
| obn | Oberon 2 Module Source Code |
| obr | Borland C++ Object Browser Data |
| obs | Objeck Source Code |
| ObjectScript Script |
| obv | ObjectScript Form |
| obyx | Obyx Script |
| oc | Esterel Compiler Automaton Code |
| oca | Visual Basic Control TypeLib Cache |
| ocaml | OCaml Source Code |
| ocb | Origin Code Builder Object |
| occ | CC5X C Compiler Output File |
| ocl | Object Constraint Language File |
| ocml | OCaml Source Code |
| octest | Xcode Objective-C Unit Test Bundle |
| ocz | Origin Encrypted C Source Code |
| od | Atari Jaguar Debugger Script |
| Atari Jaguar DRI/Alcyon Format Data |
| Atari Jaguar DSP Assembly Source |
| odb | Psion OVAL Database |
| odc | OpenDCL File |
| odcl | OpenDCL File |
| odd | TEI Source Code |
| odex | Android Optimized Dalvik Executable |
| odg | Psion OVAL Dialog File |
| odh | Visual Studio Interface Definition Language Data |
| odkbuild | ODK Build Form |
| odl | Object Description Language |
| odp | OPRO Direct to Print File |
| oem | Windows OEM Setup File |
| ofd | OPRO Form Data |
| ofp | Objecteering Project |
