Examine source code of Grey-Thunder

{
  "name": "Grey-Thunder",
  "manifest_version": 2,
  "version": "5.0",
  "theme": {
    "images": {
      "theme_frame": "grey-thunder-6.png"
    },
    "colors": {
      "frame": "rgba(229, 230, 232, 1)",
      "tab_background_text": "rgba(255, 255, 255, 1)",
      "toolbar": "rgba(31, 31, 31, 0.83)",
      "bookmark_text": "rgba(255, 255, 255, 1)",
      "toolbar_field": "rgba(3, 3, 3, 1)",
      "toolbar_field_text": "rgba(255, 255, 255, 1)",
      "tab_line": "rgba(224, 224, 224, 0.31)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{dae44d31-7bc9-46f6-9e11-d949598fdd58}"
    }
  }
}