Examine source code of Rainbow

{
  "name": "Rainbow",
  "manifest_version": 2,
  "version": "4.1resigned1",
  "theme": {
    "images": {
      "theme_frame": "Rainbow Header.jpg"
    },
    "colors": {
      "frame": "rgba(0, 0, 85, 1)",
      "tab_background_text": "rgba(255, 255, 255, 1)",
      "toolbar": "rgba(255, 255, 255, 0)",
      "bookmark_text": "rgba(255, 255, 255, 0.95)",
      "toolbar_field": "rgba(255, 255, 255, 0)",
      "toolbar_field_text": "rgba(255, 255, 255, 0.95)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{c1491233-f25a-475c-8ae0-a31981134413}"
    }
  }
}