Examine source code of Color Helper Picker

{
  "manifest_version": 2,
  "name": "Color Picker",
  "version": "1.0",
  "description": "Pick colors from any webpage and view their HEX and RGB values.",
  "permissions": [
    "activeTab"
  ],
  "browser_action": {
    "default_popup": "popup.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{b7266fde-7410-4539-9b0c-a947b59c1335}"
    }
  }
}