Examine source code of ニコニ広告ex.

{
  "manifest_version": 2,
  "name": "ニコニ広告ex.",
  "version": "2.1.4",
  "description": "ニコニコ動画・生放送内のニコニ広告を生放送ギフトのようにコメント欄に表示させます。",
  "icons": {
    "16": "images/icon16.png",
    "32": "images/icon32.png",
    "48": "images/icon48.png",
    "128": "images/icon128.png",
    "500": "images/icon500.png"
  },
  "content_scripts": [
    {
      "matches": [
        "https://www.nicovideo.jp/watch/*"
      ],
      "js": [
        "js/jquery-3.5.1.min.js",
        "js/video_script.js"
      ],
      "css": [
        "css/nicovideo.css"
      ]
    },
    {
      "matches": [
        "https://live.nicovideo.jp/watch/*",
        "https://live2.nicovideo.jp/watch/*"
      ],
      "js": [
        "js/jquery-3.5.1.min.js",
        "js/live_script.js"
      ],
      "css": [
        "css/nicolive.css"
      ]
    },
    {
      "matches": [
        "https://dic.nicovideo.jp/*",
        "https://seiga.nicovideo.jp/seiga/*",
        "https://3d.nicovideo.jp/*"
      ],
      "js": [
        "js/jquery-3.5.1.min.js",
        "js/overlay_scripts.js"
      ],
      "css": [
        "css/overlay.css"
      ]
    },
    {
      "matches": [
        "https://koken.nicovideo.jp/ticket?nicoadex",
        "https://koken.nicovideo.jp/creator?nicoadex"
      ],
      "js": [
        "js/jquery-3.5.1.min.js",
        "popup_files/js/open_newtabs.js"
      ],
      "all_frames": true
    }
  ],
  "browser_action": {
    "default_icon": "images/icon128.png",
    "default_title": "ニコニ広告ex.",
    "default_popup": "popup_files/popup.html"
  },
  "permissions": [
    "*://*.nicovideo.jp/"
  ],
  "web_accessible_resources": [
    "images/icon128.png",
    "images/logo.png"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{b1e3200d-631a-47d8-b111-a9c249a4115a}"
    }
  }
}