Examine source code of Auto Signature

{
  "manifest_version": 2,
  "name": "Auto Signature",
  "version": "1.0",
  "description": "Automatically insert a signature when commenting or sending emails.",
  "permissions": [
    "storage",
    "activeTab",
    "tabs"
  ],
  "icons": {
    "48": "icon.png"
  },
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "options_ui": {
    "page": "options.html",
    "open_in_tab": true
  },
  "browser_action": {
    "default_icon": "icon.png",
    "default_title": "Auto Signature"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{afab5fe3-a115-45c3-9327-ec46b662f20d}"
    }
  }
}