Examine source code of Word Counter Basic

{
  "manifest_version": 2,
  "name": "Word Counter",
  "version": "1.0",
  "description": "Word Counter. This utility counts the number of words and characters in the text that the user enters.",
  "permissions": [],
  "browser_action": {
    "default_popup": "game.html",
    "default_icon": {
      "128": "images/word-logo.png"
    }
  },
  "icons": {
    "128": "images/word-logo.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{faaf41b2-5118-4d43-9151-09fc486bdf32}"
    }
  }
}