Examine source code of Metallic Blue

{
  "name": "Metallic Blue",
  "manifest_version": 2,
  "version": "2.0",
  "theme": {
    "images": {
      "theme_frame": "Untitled.png"
    },
    "colors": {
      "frame": "rgba(40, 50, 67, 1)",
      "tab_background_text": "rgba(255, 255, 255, 1)",
      "toolbar": "rgba(90, 88, 88, 1)",
      "bookmark_text": "rgba(255, 255, 255, 1)",
      "toolbar_field": "rgba(40, 50, 67, 1)",
      "toolbar_field_text": "rgba(255, 255, 255, 1)",
      "tab_line": "rgba(255, 255, 255, 0)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{bff5ff84-2500-43f6-a3da-e15f7b920cef}"
    }
  }
}