Examine source code of PogChamp Universe

{
  "manifest_version": 2,
  "name": "PogChamp Universe",
  "version": "1.0",
  "description": "Replace PogChamp with people from across the universe",
  "icons": {
    "16": "icons/icon16.png",
    "48": "icons/icon48.png",
    "128": "icons/icon128.png"
  },
  "permissions": [
    "<all_urls>",
    "activeTab"
  ],
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "./ext-shim.js",
        "./pogsub.js"
      ]
    }
  ],
  "web_accessible_resources": [
    "images/*.png"
  ]
}