Examine source code of Upsell Blocker

{
  "name": "Upsell Blocker",
  "description": "Block upsell content at Amazon.",
  "version": "0.8",
  "manifest_version": 2,
  "browser_action": {
    "icons": {
      "16": "icons/upsellblockicon16x16.png",
      "32": "icons/upsellblockicon32x32.png",
      "48": "icons/upsellblockicon32x32.png"
    },
    "default_popup": "html/popup.html"
  },
  "content_scripts": [
    {
      "matches": [
        "https://*.amazon.com/*"
      ],
      "js": [
        "/scripts/amazon.js"
      ]
    }
  ]
}