Examine source code of Character Counter

{
  "manifest_version": 2,
  "name": "Character Counter",
  "description": "Count the characters, words, sentences, paragraphs & whitespaces in a text.",
  "author": "Tikam Chand",
  "homepage_url": "http://www.tcmhack.in",
  "version": "0.0.1",
  "version_name": "Basic - 0.0.1",
  "browser_action": {
    "default_icon": "icon.png",
    "default_title": "Character/Words Counter.",
    "default_popup": "popup.html"
  },
  "icons": {
    "16": "icon.png",
    "22": "icon.png",
    "32": "icon.png",
    "48": "icon.png",
    "128": "icon.png"
  },
  "offline_enabled": true,
  "web_accessible_resources": [
    "images/*",
    "fonts/*",
    "css/*"
  ]
}