Examine source code of Unknown Calls

{
  "manifest_version": 2,
  "name": "TheUnknownCall",
  "version": "1.0",
  "description": "Free reverse phone number lookup",
  "homepage_url": "https://www.theunknowncall.com",
  "icons": {
    "50": "icon-50.png"
  },
  "background": {
    "scripts": [
      "common.js"
    ]
  },
  "browser_action": {
    "default_icon": "icon-32.png",
    "default_title": "TheUnknownCall",
    "default_popup": "popup.html"
  }
}