In ST2, you can directly open the .tmTheme files in the program directory, and edit the colour scheme. In ST3 -- at least the portable version -- that doesn't seem to be possible. There is no file named "Monokai" anywhere in the program files, or in %appdata%.
If you go to edit the user settings, by default it is using the colour scheme "/Packages/Color Scheme - Default/Monokai.tmTheme". Only that's not a directory that exists... there's no /Color Scheme - Default/. There's a FILE by that name, a .sublime-package file, and when you extract it using 7zip you can get a full theme folder, the way it's seen in ST2. But if you then try to point to one of those tmThemes in the user settings, you get this error.
Error loading colour scheme. Unable to open.
So my question is... exactly how is it possible to edit the colour schemes in the current portable version of Sublime Text 3 for Windows?