| bet | BETA Source Code |
| beta | BETA Source Code |
| bfo | GT Nexus PDF Template |
| bgm | Basic4GL 3D Model |
| bi | BSC Intermediate Object |
| bi | OpenEdge ABL Before Image |
| bin | Windows CE Emulator Image |
| bld | SPLat Build File |
| blk | ProWorx NXT Block Data File |
| bltx | BlaTeX Source Code |
| bluej | BlueJ Package |
| bml | Alpha Five Image Library |
| bmt | Alpha Five Image Library |
| bmx | Alpha Five Image Library |
| bo | BSC Intermediate Object |
| boc | Hitachi Ladder Editor Box Comment |
| bog | Niagara Ax BOG FIle |
| bok | ProStores Dynamic Web Page |
| boot | InstallShield Boot File |
| bpg | Borland Project Group |
| bpi | Borland Package Import |
| bpk | Borland Package |
| bpl | Borland Package Library |
| bql | SensorBee BQL Script |
| br | Omnis Studio Data File |
| brc | BASIS Binary Resource Data |
| brh | BREW Application Resource Header File |
| browser | ASP.NET Browser Definition |
| brx | BREW Application Resource File |
| bs2 | BASIC Stamp 2 Code |
| bsc | Visual Studio Browser Information |
| bsf | Altera Quartus II Block Symbol File |
| bsh | BeanShell Script |
| bsx | PBASIC Preprocessor Output |
| bte | BTEWin Script |