Examine source code of imperiariverview

{
  "name": "imperiariverviewlongbien",
  "manifest_version": 2,
  "version": "1.0",
  "theme": {
    "images": {
      "theme_frame": "imperiariverview.jpg"
    },
    "colors": {
      "frame": "rgba(44, 67, 122, 1)",
      "tab_background_text": "rgba(204, 16, 16, 1)",
      "toolbar_field_text": "rgba(143, 63, 63, 1)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{d5f68bf5-eac1-4aae-a992-4549b1fd9670}"
    }
  }
}