Examine source code of YouTube Play All Button

{
  "manifest_version": 3,
  "name": "YouTube Play All Button",
  "version": "1.0.2",
  "description": "Adds a 'Play All' button to YouTube channel pages",
  "permissions": [
    "tabs",
    "storage"
  ],
  "host_permissions": [
    "https://*.youtube.com/*"
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "type": "module"
  },
  "content_scripts": [
    {
      "matches": [
        "https://*.youtube.com/*"
      ],
      "run_at": "document_end",
      "js": [
        "add_button.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "deshpandetanmay2003@gmail.com"
    }
  },
  "icons": {
    "128": "logo.png"
  },
  "action": {
    "default_icon": {
      "128": "logo.png"
    },
    "default_title": "YouTube Play All Button"
  },
  "homepage_url": "https://github.com/deshpandetanmay03/youtube-playall-button"
}