Examine source code of Old Reddit Tweaker

{
  "manifest_version": 2,
  "name": "Old Reddit Tweaker",
  "version": "1.24",
  "description": "Enhances old.reddit.com with subreddit filtering, redirecting to old.reddit.com, expanding image/YouTube links, removing notification icons, and auto-expanding comments.",
  "permissions": [
    "storage",
    "webNavigation",
    "https://*.reddit.com/*"
  ],
  "icons": {
    "48": "icons/icon-48.png",
    "96": "icons/icon-96.png"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "https://old.reddit.com/*"
      ],
      "exclude_matches": [
        "https://old.reddit.com/r/*/comments/*"
      ],
      "css": [
        "styles.css"
      ],
      "js": [
        "content.js"
      ]
    },
    {
      "matches": [
        "https://old.reddit.com/r/*/comments/*"
      ],
      "css": [
        "styles.css"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "options_ui": {
    "page": "options.html",
    "browser_style": true
  },
  "browser_action": {
    "default_icon": {
      "48": "icons/icon-48.png",
      "96": "icons/icon-96.png"
    },
    "default_popup": "options.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{52a82a13-bf36-4673-b08f-18e1534479d4}"
    }
  }
}