Examine source code of dark field

{
  "theme": {
    "images": {
      "theme_frame": "1223335201921.JPG"
    },
    "colors": {
      "frame": "#6e940d",
      "tab_background_text": "#b7e045"
    }
  },
  "version": "2.0",
  "name": "dark field",
  "manifest_version": 2
}