Examine source code of PageProof online proofing

{
  "manifest_version": 2,
  "name": "PageProof. Online proofing, review & approval",
  "short_name": "PageProof",
  "description": "The perfect extension to PageProof. Let’s make reviewing and approving creative work effortless.",
  "version": "3.1.0",
  "homepage_url": "https://app.pageproof.com",
  "icons": {
    "16": "assets/images/icon16-production.png",
    "32": "assets/images/icon32-production.png",
    "48": "assets/images/icon48-production.png",
    "128": "assets/images/icon128-production.png"
  },
  "browser_action": {
    "default_icon": "assets/images/icon32-production.png"
  },
  "web_accessible_resources": [
    "worker.*.js"
  ],
  "content_scripts": [
    {
      "matches": [
        "https://app.pageproof.com/*"
      ],
      "js": [
        "pageproof.bundle.js"
      ]
    },
    {
      "matches": [
        "*://www.canva.com/design/*/*/edit*"
      ],
      "js": [
        "patch-worker.js",
        "canva.bundle.js"
      ]
    },
    {
      "matches": [
        "https://app.pageproof.com/_private/embed-login/*"
      ],
      "js": [
        "pageproof-embed-login.bundle.js"
      ],
      "all_frames": true,
      "run_at": "document_end"
    },
    {
      "matches": [
        "http://*/*",
        "https://*/*"
      ],
      "js": [
        "cookie-interceptor-relay.bundle.js"
      ],
      "all_frames": true,
      "run_at": "document_start"
    }
  ],
  "background": {
    "scripts": [
      "event.bundle.js",
      "web-url-proofing.bundle.js"
    ],
    "persistent": true
  },
  "permissions": [
    "tabs",
    "webNavigation",
    "webRequest",
    "webRequestBlocking",
    "cookies",
    "http://*/",
    "https://*/",
    "<all_urls>"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{426d0505-eb5b-4adf-8755-60e19167c606}"
    }
  }
}