User JavaScript and CSS

manifest.json

{
  "update_url": "https://clients2.google.com/service/update2/crx",
  "manifest_version": 2,
  "name": "User JavaScript and CSS",
  "short_name": "User JS and CSS",
  "description": "__MSG_description__",
  "version": "2.1.1",
  "minimum_chrome_version": "80",
  "permissions": [
    "storage",
    "unlimitedStorage",
    "http://*/",
    "https://*/",
    "tabs"
  ],
  "background": {
    "page": "background.html"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_start"
    }
  ],
  "icons": {
    "16": "img/logo_16.png",
    "48": "img/logo_48.png",
    "128": "img/logo_128.png"
  },
  "options_page": "options.html",
  "web_accessible_resources": [
    "js/libs/jquery.min.js"
  ],
  "browser_action": {
    "default_popup": "popup.html"
  },
  "sandbox": {
    "pages": [
      "sandbox.html"
    ]
  },
  "default_locale": "en"
}