Examine source code of Easy Currency Converter

{
  "manifest_version": 2,
  "name": "Quick Currency Converter",
  "version": "1.0",
  "description": "Converts highlighted currency amounts to a selected currency via the context menu.",
  "permissions": [
    "contextMenus",
    "storage",
    "activeTab",
    "http://api.exchangerate-api.com/"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "options_ui": {
    "page": "options/options.html",
    "open_in_tab": false
  },
  "browser_action": {
    "default_icon": {
      "48": "icons/icon-48.png"
    },
    "default_title": "Currency Converter Options",
    "default_popup": "options/options.html"
  },
  "icons": {
    "48": "icons/icon-48.png",
    "96": "icons/icon-96.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "currency-converter@EyasDmour.com",
      "strict_min_version": "58.0"
    }
  }
}