Examine source code of Character Limit Textarea

{
  "manifest_version": 2,
  "name": "Character Limit Textarea",
  "version": "1.0",
  "description": "In this application, we will display the text area as an input component to the user and there is a predefined limit set to accept the input. When the limit is been crossed the user will get the alert message and he will not be able to type further in the text area.",
  "permissions": [],
  "browser_action": {
    "default_popup": "game.html",
    "default_icon": {
      "128": "images/limit-logo.png"
    }
  },
  "icons": {
    "128": "images/limit-logo.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{c73c780b-b4fa-42a7-8c0c-23b8997f32da}"
    }
  }
}