Examine source code of YouTube Selection Search

{
  "manifest_version": 2,
  "name": "YouTube Selection Search",
  "version": "1.0",
  "description": "Search selected text on YouTube.",
  "permissions": [
    "contextMenus",
    "tabs"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "youtube-selection-search@example.com",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  }
}