Examine source code of Space Discovery

{
  "name": "Space Discovery",
  "manifest_version": 2,
  "version": "3.0",
  "theme": {
    "images": {
      "theme_frame": "header.png"
    },
    "colors": {
      "frame": "rgba(232, 233, 235, 0)",
      "tab_background_text": "#ffffff",
      "toolbar": "rgba(0, 0, 0, 0)",
      "bookmark_text": "rgba(255, 255, 255, 1)",
      "toolbar_field": "rgba(0, 0, 0, 0)",
      "toolbar_field_text": "rgba(255, 255, 255, 1)",
      "tab_line": "rgba(217, 214, 41, 1)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{521c51dc-e4ab-44a2-b15e-f2c83d158175}"
    }
  }
}