Examine source code of Rooster..

{
  "name": "Rooster..",
  "manifest_version": 2,
  "version": "4.0",
  "theme": {
    "images": {
      "theme_frame": "RoosterH2.jpg"
    },
    "colors": {
      "frame": "rgba(61, 41, 29, 1)",
      "tab_background_text": "rgba(255, 235, 153, 1)",
      "toolbar": "rgba(61, 42, 29, 0)",
      "bookmark_text": "rgba(252, 227, 146, 1)",
      "toolbar_field": "rgba(61, 42, 29, 0.1)",
      "toolbar_field_text": "rgba(250, 244, 163, 1)",
      "tab_line": "rgba(250, 244, 163, 1)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{654bd6c6-287c-4b75-ae54-f0e5a97bc2b6}"
    }
  }
}