Examine source code of CF AC Companion

{
  "manifest_version": 3,
  "name": "CF AC Companion",
  "version": "1.0.0",
  "description": "Compact ratings, tag controls, solved-state feedback, timers, and Gym/Mashup support for Codeforces.",
  "browser_specific_settings": {
    "gecko": {
      "id": "cf-ac-companion@local",
      "strict_min_version": "142.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "permissions": [
    "alarms",
    "storage",
    "activeTab",
    "scripting"
  ],
  "host_permissions": [
    "https://codeforces.com/*"
  ],
  "action": {
    "default_popup": "popup/popup.html",
    "default_icon": {
      "16": "icons/icon16.png",
      "48": "icons/icon48.png",
      "128": "icons/icon128.png"
    }
  },
  "background": {
    "service_worker": "src/background.js",
    "scripts": [
      "src/background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "https://codeforces.com/problemset/problem/*",
        "https://codeforces.com/contest/*/problem/*"
      ],
      "js": [
        "src/content.js"
      ],
      "css": [
        "styles/content.css"
      ],
      "run_at": "document_idle"
    },
    {
      "matches": [
        "https://codeforces.com/problemset*"
      ],
      "js": [
        "src/problemset.js"
      ],
      "css": [
        "styles/content.css"
      ],
      "run_at": "document_idle"
    },
    {
      "matches": [
        "https://codeforces.com/gym/*/problem/*",
        "https://codeforces.com/gym/*/mashup/*",
        "https://codeforces.com/contest/*/mashup/*"
      ],
      "js": [
        "src/gym.js"
      ],
      "css": [
        "styles/content.css"
      ],
      "run_at": "document_idle"
    }
  ],
  "icons": {
    "16": "icons/icon16.png",
    "48": "icons/icon48.png",
    "128": "icons/icon128.png"
  }
}