Examine source code of Instagram Calculator

{
  "manifest_version": 2,
  "name": "Instagram Calculator by IMH",
  "version": "1.1",
  "icons": {
    "32": "icons/favicon.png"
  },
  "permissions": [
    "<all_urls>",
    "tabs"
  ],
  "browser_action": {
    "default_icon": {
      "32": "icons/favicon.png"
    },
    "default_title": "Instagram Calculator",
    "default_popup": "popup/content-script.html",
    "browser_style": true
  }
}