Examine source code of Comment icon

{
  "manifest_version": 2,
  "name": "Comment icon",
  "version": "1.0",
  "description": "Comment icons used under articles, social networking sites, websites...",
  "icons": {
    "48": "icon.png"
  },
  "browser_action": {
    "default_icon": "icon.png",
    "default_popup": "popup.html",
    "default_title": "Click me!"
  },
  "permissions": [
    "activeTab"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{ff7caac5-184a-4f10-addc-b24d8c4e7e6a}"
    }
  }
}