Examine source code of macOS Sierra Dark Theme

{
  "theme": {
    "images": {
      "theme_frame": "header.png"
    },
    "colors": {
      "frame": "#bababa",
      "tab_background_text": "#f7f4f4"
    }
  },
  "version": "2.0",
  "name": "macOS Sierra Dark Theme",
  "manifest_version": 2,
  "description": "A Solid black theme to match macOS Sierra's new Dark Theme. Also works well with Mac OS X Yosemite's Dark Theme."
}