TL;DR: The files aren’t there because Sublime won’t load them anyway. If you want to see what the defaults are for other platforms you can use PackageResourceViewer to view the Default package, but you can’t have platform specific settings in your User package.
More verbosely:
The general rules Sublime uses for loading preference files is:
- FIles with the same name in multiple packages are merged together as one file, in package load order
- The order that packages are loaded is alphabetical by name, except that the
Default package is always loaded first and the User package is always loaded last.
- If a settings file name contains a platform designation, such as (Linux), (Windows) or (OSX), that settings file is only loaded on the platform named
- Sublime will not load a platform specific settings file from the
User package
With that out of the way and to answer your question more specifically, the Default package (which ships with sublime) contains the following files:
Preferences.sublime-settings
Preferences (Windows).sublime-settings
Preferences (Linux).sublime-settings
Preferences (OSX).sublime-settings
The first one is the file that you see in the left pane when you use Preferences > Settings from the menu. It specifies the default values for all (documented) settings. The other three files contain only overrides for settings specific to an operating system. For example the font_face setting, which defaults to Consolas on Windows, Monospace on Linux and Menlo-Regular on OSX which are presumably the most common font available on each system.
The reason you can’t find such files in your User folder is due to rule #4 above: Sublime won’t load files that are platform specific from the User folder, so it doesn’t create them there.
If you truly want to have different platform specific settings per platform it gets tricky; if you put them in your User package, they won’t load, and if you put them in some other package you can’t guarantee that the package load order will make sure that the setting doesn’t get overridden somewhere along the line.