Examine source code of Simple Prices

{
  "manifest_version": 2,
  "name": "Simple Prices",
  "description": "Shows simple, rounded prices after a short delay to combat manipulation and clutter. Want to check the actual price? Just reload the page or turn off the addon by clicking on its icon.",
  "version": "1.0.1",
  "icons": {
    "48": "icons/icon.png",
    "96": "icons/icon@2x.png"
  },
  "browser_action": {
    "default_icon": "icons/icon.png",
    "default_title": "Simple Prices"
  },
  "background": {
    "scripts": [
      "./background.js"
    ]
  },
  "permissions": [
    "activeTab",
    "tabs",
    "storage"
  ],
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "exclude_matches": [
        "*://*.youtube.com/*"
      ],
      "js": [
        "./substitute.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{8f0c8cad-ef42-473c-99e3-fab1174421d8}"
    }
  }
}