Dim the Internet - Turn down the brightness.

manifest.json

{
  "update_url": "https://clients2.google.com/service/update2/crx",
  "name": "Dim the Internet - Turn down the brightness.",
  "manifest_version": 3,
  "version": "1.0",
  "description": "Simply drag a slider to dim every single website.",
  "permissions": [
    "scripting",
    "storage"
  ],
  "host_permissions": [
    "<all_urls>"
  ],
  "action": {
    "default_popup": "popup.html"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content_script.js"
      ]
    }
  ],
  "icons": {
    "16": "icon16.png",
    "128": "icon128.png"
  }
}