Examine source code of Blue Marble

{
  "name": "Traces on the wall",
  "manifest_version": 2,
  "version": "2.0",
  "theme": {
    "images": {
      "theme_frame": "marmor-1.png"
    },
    "colors": {
      "frame": "rgba(229, 230, 232, 1)",
      "tab_background_text": "rgba(209, 209, 209, 1)",
      "toolbar": "rgba(3, 19, 20, 0.75)",
      "bookmark_text": "rgba(255, 255, 255, 1)",
      "toolbar_field": "rgba(89, 82, 64, 0.49)",
      "toolbar_field_text": "rgba(255, 255, 255, 1)",
      "tab_line": "rgba(128, 130, 138, 1)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{42db0ef7-76a1-4bb8-b1df-de12a8a0c933}"
    }
  }
}