How much information do pdb files contain? (C# / .NET)

It basically adds information for:

• All non-public types, interfaces, structures, classes
• Local variables in functions
• Source file names for relevant code and corresponding line numbers in source code.

which all combined makes reverse engineering very easy for native code.

Luckily you can create a stripped down version of your PDB files which only contains public information with /PDBSTRIPPED parameter.

Oh you edited to add C#/.NET, so I'm not sure if "PDBSTRIPPED" is applicable. However .NET applications are very easy to reverse engineer even without any symbol information. I wouldn't mind including them in a .NET project.

You could try using dia2dump to look at the contents.