Examine source code of Convert (crypto)currency

{
  "manifest_version": 2,
  "name": "Convert (crypto)currency",
  "description": "Context menu option to convert selected crypto/fiat value - displays the result in a simple tooltip.",
  "version": "1.5",
  "icons": {
    "128": "exchange.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "crypto-context-bhspiers@gmail.com"
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "api.js",
        "crypto-context.js"
      ]
    }
  ],
  "permissions": [
    "https://api.coinbase.com/*",
    "contextMenus",
    "storage",
    "activeTab"
  ],
  "options_ui": {
    "page": "options.html",
    "open_in_tab": false
  }
}