Examine source code of Play All

{
  "manifest_version": 2,
  "name": "Play All",
  "version": "0.1",
  "description": "Play all of a YouTube channel's videos in one page",
  "browser_action": {},
  "content_scripts": [
    {
      "matches": [
        "*://*.youtube.com/*"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "background": {
    "scripts": [
      "script.js"
    ],
    "persistent": false,
    "type": "module"
  },
  "content_security_policy": "default-src 'self' *.youtube.com youtube.com https://*.youtube.com https://youtube.com; script-src 'self' *.youtube.com youtube.com https://*.youtube.com https://youtube.com",
  "browser_specific_settings": {
    "gecko": {
      "id": "{e509a759-9bbe-4111-8b44-a752583257d9}"
    }
  }
}