Examine source code of Word Count Popup

{
  "manifest_version": 2,
  "name": "Word Count Popup",
  "version": "1.0",
  "description": "Count words and characters from a popup textarea.",
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": "icon.png",
    "default_title": "Word Count Popup"
  },
  "permissions": [],
  "icons": {
    "48": "icon.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{ed12cec1-937a-42fc-b93b-10bb9c46d6b7}"
    }
  }
}