The .pdb filename extension refers to the program database file format authored by Microsoft. The format is used for storing debugging information about executable files and programming libraries or DLL files. The pdb format was designed to ease the debugging process of executables and program modules by decoupling the debugging information from the end of the program or class library itself to allow the integrated debugger and linker to access the pdb files directly. It doing so, the PDB format facilitates the stepping into/out of runtime libraries. The format and its internals remain the proprietary asset of Microsoft.