Temporary Path is first group in System Settings.
If you have saved the current scene, the script will create a Smart Merge folder where the file is saved, and extract everything into it, else if you haven’t saved the current scene (Untitled), everything will be extracted to this path.
Note that, by default, the script will always create a folder named Smart Merge before extracting. So if the Temporary Path is “C:\”, it will actually extract to the folder “C:\Smart Merge”.