Examine source code of DivCounter

{
  "manifest_version": 2,
  "name": "DivCounter",
  "version": "0.1",
  "description": "A simple div counter",
  "homepage_url": "https://github.com/Fimeo/divcounter",
  "icons": {
    "48": "icons/counter.png"
  },
  "permissions": [
    "activeTab"
  ],
  "browser_action": {
    "default_icon": "icons/counter-32.png",
    "default_title": "DivCounter",
    "default_popup": "popup/div_counter.html"
  }
}