So MSVC use PDB format which is undocumented. LLVM want to implement PDB. LLVM asks MS for help MS disclose the portion of the MSVC code which deal with PDB

So MSVC use PDB format which is undocumented. LLVM want to implement PDB. LLVM asks MS for help MS disclose the portion of the MSVC code which deal with PDB MS GitHub even says "Source code is the ultimate documentation :-)" I think even the MS doesn't have formal documentation for PDB format.