Examine source code of Share by e-mail

{
  "manifest_version": 2,
  "name": "Share by e-mail",
  "version": "2.0",
  "description": "Share url address by e-mail",
  "icons": {
    "128": "icon.png"
  },
  "permissions": [
    "tabs"
  ],
  "browser_action": {
    "default_title": "Share by e-mail",
    "default_icon": "icon.png",
    "default_popup": "background.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{d10d8e93-b009-4d8e-b1ac-83b822667c46}"
    }
  }
}