Where is my game save file saved to?

The save file is always created at the application persistent data path. This is done to ensure it will work for all platforms. You can access the save file quickly via the yellow button is the project settings for the asset:

Pressing this will open the save file location one directory back from the file with the folder to continue highlighted. Just enter that folder to find the save.sf file with your data. Note in builds this will not be the save file for the game unless you are building for PC/Mac/Linux. To find out where it is stored on build please see the persistent data path information here: https://docs.unity3d.com/ScriptReference/Application-persistentDataPath.html