The function used to return "TrueString" or "FalseString" back then. Nowadays it returns "True" or "False".
https://blog.jetbrains.com/dotnet/2015/02/12/string-internin...
The StackOverflowers note that the implementation technically doesn't match the spec, but in a way which can only be observed by using reflection https://stackoverflow.com/questions/491334#comment34617036_4...