The default OS X SDK path is in Application’s Content package;
1- goto Applications Folder -> Xcode
2- Right-click to Xcode, select “Show Package Contents”
3- Navigate to Developer->Platforms-> MacOSX.platform->Developer->SDKs
It’s possible to see folder path in Finder with the help of one line of code in terminal. To enable folder path view, copy and paste the as follows;
defaults write com.apple.finder _FXShowPosixPathInTitle -bool YES
And to make it work instantly, you should restart or refresh Finder as it follows from Terminal window again;
killall Finder
To revert it back, just type the same codes and change boolean type YES
to NO
defaults write com.apple.finder _FXShowPosixPathInTitle -bool YES killall Finder