Examine source code of Daydream Night Mode

{
  "manifest_version": 3,
  "name": "Daydream Night Mode",
  "version": "0.1.7",
  "description": "Get rid of the sun-like pages and have a sweet Daydream...",
  "permissions": [
    "activeTab",
    "tabs",
    "storage",
    "scripting"
  ],
  "host_permissions": [
    "https://*/*",
    "http://*/*",
    "ftp://*/*",
    "file://*/*"
  ],
  "background": {
    "scripts": [
      "service-worker.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "https://*/*",
        "http://*/*",
        "ftp://*/*",
        "file://*/*"
      ],
      "css": [
        "content.css"
      ],
      "run_at": "document_start",
      "match_about_blank": true
    }
  ],
  "action": {
    "default_popup": "popup.html"
  },
  "icons": {
    "128": "DaydreamIcon.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "zankyostudio@gmail.com"
    }
  }
}