The DEB file extension is used for Debian packages. DEB files are standard Unix archives and each contains two compressed archives. DEB files are used in Debian Linux operating system.
The DEB file extension is used by MS-DOS Debug as debug script. debug is a command in DOS, OS/2 and Microsoft Windows which runs the program debug.exe (or DEBUG.COM in older versions of DOS). Debug can act as an assembler, disassembler, or hex dump program allowing users to interactively examine memory contents (in assembly language, hexadecimal or ASCII), make changes, and selectively execute COM, EXE and other file types.