Examine source code of readable-internet

{
  "manifest_version": 2,
  "name": "Readable Internet",
  "description": "A browser extension that makes the web more readable",
  "version": "1.0.1",
  "icons": {
    "16": "icons/16.png",
    "32": "icons/32.png",
    "48": "icons/48.png",
    "128": "icons/128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "readable-internet@codeberg.org",
      "data_collection_permissions": {
        "required": [
          "authenticationInfo",
          "websiteContent"
        ]
      }
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_title": "Readable Internet",
    "default_popup": "popup.html"
  },
  "content_scripts": [
    {
      "matches": [
        "https://*.reddit.com/*",
        "https://*.x.com/*"
      ],
      "js": [
        "content-scripts/content.js"
      ]
    }
  ],
  "permissions": [
    "https://*.reddit.com/*",
    "https://*.x.com/*"
  ]
}