Because it isn't always as simple as
as is done in
Mono.Cecil.Pdb.PdbHelper, if assemblies and symbols have been moved to separate locations during a build.
The tools are there -- we just need to get the debug data from the PE image if it's present, skip the first 24 bytes, and interpret the rest as a string. Alas, all the are annoyingly just slightly encapsulated from us. But never mind! Reflection gets us there without having to negotiate a patch or make a fork: