Unturned save location on Mac

Found my answer.

On Mac OS X PlayerPrefs are stored in ~/Library/Preferences folder, in a file named unity.[company name].[product name].plist, where company and product names are the names set up in Project Settings. The same .plist file is used for both Projects run in the Editor and standalone players.

Source: http://docs.unity3d.com/ScriptReference/PlayerPrefs.html

For Unturned, the file should be called: unity.Smartly Dressed Games.Unturned.plist

Deleting this file, will not result in inventory changing. I think this is because of a recent update that introduced Steam Cloud Save.

Unturned save on OS X is located at:

~/Library/Preferences/unity.Smartly\ Dressed\ Games.Unturned.plist

If you would like to backup your data, just copy the plist file.

To restore the save you backed up, first copy your backup to the original file mentioned above. Then, invalidate plist caches kept by OS to ensure that Unturned will use the restored data. You can invalidate the caches by executing:

killall -u $USER cfprefsd

on Terminal.

See objective c - Deleting plist file does not reset app on Mac OS 10.9 Mavericks - Stack Overflow for more information about plist cache invalidation.