Examine source code of Random Subreddit Button

{
  "name": "Random Subreddit Button",
  "version": "3.0",
  "description": "Adds a button to Reddit to visit random subreddits",
  "icons": {
    "16": "icon16.png",
    "48": "icon48.png",
    "96": "icon96.png",
    "128": "icon128.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.reddit.com/*"
      ],
      "js": [
        "rsb.js"
      ],
      "css": [
        "bubbler.css"
      ]
    }
  ],
  "manifest_version": 3,
  "browser_specific_settings": {
    "gecko": {
      "id": "{c2ee1da7-024c-41ad-a26a-abbbf2cf4b80}",
      "strict_min_version": "42.0"
    }
  }
}