Examine source code of Quick Calculator

{
  "author": "M Zaheer",
  "browser_action": {
    "default_icon": "icon.png",
    "default_popup": "popup.html",
    "default_title": "Calculator"
  },
  "commands": {
    "_execute_browser_action": {
      "suggested_key": {
        "chromeos": "Alt+C",
        "default": "Alt+C",
        "linux": "Alt+C",
        "mac": "Alt+C",
        "windows": "Alt+C"
      }
    }
  },
  "content_security_policy": "script-src 'self' 'unsafe-eval' https://www.google-analytics.com; object-src 'self'",
  "description": "It gives you all common parameters for the calculations easily.",
  "icons": {
    "128": "icon128.png"
  },
  "key": "MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAuIYXLiGDrzoyGIU5IFdl5a7TfDzAYVPyQQAnzeHKhWuW33TITH7Q/nQXUtsYnWKpnHLC+5jVBOFkQkxM4C20EkLiX/WqaPsmY+vgv1HoiuSRXtC1Mys3DvX/DBpDpc/Hrzvl8ugaN1/r8bkCJvzlx45Mm9ApUPOcAXCCXVyUUHq7+1o6DYeMYQ6Nqvm1xzAKCUMO+66lST21x8LhCXhTT3BG8nmgD+632rBH1jFm1GNzR7rlW2uV2uOtTSszeNGCS6H/QG6q26yl4Vznud+SgqumIWY5KOqeDIPsByc4gpYOBDT2rMfvt66tSeJKjJA7SAv5au/e567qqDlQfethLQIDAQAB",
  "manifest_version": 2,
  "name": "Quick Calculator",
  "offline_enabled": true,
  "options_page": "options.html",
  "short_name": "Calculator",
  "update_url": "https://clients2.google.com/service/update2/crx",
  "version": "1.7.7",
  "browser_specific_settings": {
    "gecko": {
      "id": "{2848e19a-a30e-4937-a58e-2a83683e5d7c}"
    }
  }
}