Examine source code of ytb not-interested button

{
  "manifest_version": 3,
  "name": "ytb not-interested button",
  "description": "add do-not-interest button to video.",
  "version": "0.1.12",
  "content_scripts": [
    {
      "matches": [
        "https://www.youtube.com/*"
      ],
      "js": [
        "add_not_interested.js"
      ],
      "run_at": "document_end"
    }
  ],
  "action": {
    "default_popup": "options.html"
  },
  "icons": {
    "16": "ic_not_interested_16.png",
    "32": "ic_not_interested_32.png",
    "48": "ic_not_interested_48.png",
    "128": "ic_not_interested_128.png"
  },
  "options_ui": {
    "page": "options.html",
    "open_in_tab": false
  },
  "permissions": [
    "webNavigation",
    "storage"
  ],
  "host_permissions": [
    "https://www.youtube.com/"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "ytb-not-interested@huhuang03.com"
    }
  }
}