Examine source code of Dark Days

{
  "name": "Dark Days",
  "manifest_version": 2,
  "version": "3.0",
  "theme": {
    "images": {
      "theme_frame": "blank.png"
    },
    "colors": {
      "frame": "rgba(26, 26, 26, 1)",
      "tab_background_text": "rgba(255, 255, 255, 1)",
      "toolbar": "rgba(41, 41, 41, 1)",
      "bookmark_text": "rgba(255, 255, 255, 1)",
      "toolbar_field": "rgba(46, 46, 46, 1)",
      "toolbar_field_text": "rgba(255, 255, 255, 1)",
      "tab_line": "rgba(255, 255, 255, 1)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{fd5e8afc-e534-4d8d-8f72-f5d89055cfb4}"
    }
  }
}