Examine source code of topo3

{
  "name": "topo3",
  "manifest_version": 2,
  "version": "1.0",
  "theme": {
    "images": {
      "theme_frame": "360_F_316781115_ckiR3eI5AWPu3MUrhAcJkK8hJZFaBQXd.jpg"
    },
    "colors": {
      "frame": "rgba(120, 120, 120, 1)",
      "tab_background_text": "rgba(255, 255, 255, 1)",
      "toolbar": "rgba(120, 120, 120, 1)",
      "bookmark_text": "rgba(255, 255, 255, 1)",
      "toolbar_field": "rgba(156, 156, 156, 1)",
      "toolbar_field_text": "rgba(255, 255, 255, 1)",
      "tab_line": "rgba(120, 120, 120, 1)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{f9a7d8dc-8e06-4201-a34e-4ba7c96b95b3}"
    }
  }
}