In ST3, plugins/packages are run directly from the
.sublime-package file. For most things, you don't actually
need the contents of those files. For instance, you can create a
Preferences.sublime-settings in the user folder, and it will
be merged properly. That being said, ST3 does allow you to override files.
To make things easier, you can use the plugin PackageResourceViewer. I wrote it to assist with viewing
default files. Again, you don't need to do this for your particular case
though. In the menu, go to
Preferences -> Settings - User.
This will create a preferences file in the user directory. When merged, the
values in the
User directory will be used rather than those in