Examine source code of Channelink

{
  "manifest_version": 3,
  "name": "Channelink",
  "version": "1.10",
  "description": "Adds channel links to video suggestions in youtube's watch later list.",
  "icons": {
    "48": "icons/link.png"
  },
  "content_scripts": [
    {
      "matches": [
        "https://*.youtube.com/*"
      ],
      "js": [
        "channelink.js"
      ],
      "run_at": "document_start"
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{e3bcb2fa-71ee-499d-847d-630309c87d46}",
      "strict_min_version": "58.0"
    }
  }
}