| atn | Visual FoxPro Internet Search Wizard Data |
| atsln | Atmel Studio Solution |
| au3 | AutoIt v3 Script |
| aub | Intel GPU Simulator Input |
| aut | AutoIt Script |
| autosave | GDevelop Autosave Data |
| avm | QAvimator Document |
| avrsln | Atmel Studio Legacy Solution File |
| aw | Free Pascal Archive |
| awk | AWK Script |
| awl | Alternative Web Language Source Code |
| Siemens AWL File |
| WebDev AWP Page Library |
| awp | WebDev AWP Page |
| awws | WebDev WebService Library |
| awx | Microsoft DirectX AWX Data |
| ax | Modula-3 Linker Information |
| axb | Alpha Five Xbasic Script |
| axd | ASP.NET Trace Handler |
| axe | Annotated XML Example |
| Paradigm C++ Integrated Debugger Data |
| axf | ARM RealView Compiler Object |
| µVision Absolute and Executable Object |
| axl | ASCET Compressed Model Data |
| axml | Xamarin Android XML Layout |
| axp | AxpDataGrid Data |
| GNU Arch Extension Data |
| axs | ActiveX Script |
| aya | Ayauhteotl Parser Data |
| azcli | Microsoft Azure CLI Script |
| b | BASIC Source |
| BuRg3r Definition Data |
| Limbo Source Code |
| Modula-3 Base Program |
| b1 | OpenEdge ABL Before Image |
| b2 | OpenEdge ABL Before Image |
| b24 | Ovation Pro for RISC OS C Script |
| b25 | Ovation Pro for RISC OS DDL Data |
| b26 | Ovation Pro for RISC OS Style Sheet |
| b27 | Ovation Pro for RISC OS Document |
| b2d | Brutus2D Source Code |
| b3 | OpenEdge ABL Before Image |
| b32 | Borland C Compiler Data |
| b36 | PDP-10 BLISS-36 Compiler Source Code |
| ba | BSC Intermediate Object |
| babylon | Babylon.js Scene |
| bacpac | Microsoft SQL Server DAC Exported Package |
| bal | B4A Layout |
| baml | Compiled XAML |
| bar | BREW MP Binary Application Resource |
| dBase Application Generator Menu Bar Object |
| bas | BASIC Source |
| basex | BaseX Data |
| bash | Unix Shell Script |
| baz | Zebra Printer Basic Source Code |
| bb | Blitz Basic Code |
| GCOV BB Data |
| bb2 | Blitz Basic Code |
| bbc | BBC Basic Source Code |
| bbf | ScriptBasic Compiled Binary File |
| bbg | GCOV BBG Data |
| bbr | BlackBerry Native SDK Manifest Data |
| bc | Low Level Virtual Machine Bitcode |
| bcb | Borland C++ Builder Data |
| bcc | Borland C++ Makefile |
| bcl | PDP-10 BCPL Compiler Source Code |
| bcp | Batch Compiler Preset |
| Borland C++ AppExpert Database |
| Borland C++ Makefile |
| bcw | Borland C++ Workspace Data |
| bdat | HP-UX Binary Data File |
| bdcm | Business Data Connectivity Model Data |
| Visual Studio BDC Model Data |
| bdcr | Microsoft Visual Studio BDC Resource Data |
| bde | Borland Database Engine Data |
| bdf | Altera Quartus II Block Diagram File |
| bdh | Silk Performer Script |
| bds | EasyC Project Data |
| bdsl | Boundary-Scan Description Language File |
| bdt | TAC Script |
