Examine source code of Monotone – Grayscale & Blue Light Filter

{
  "manifest_version": 3,
  "name": "Monotone – Grayscale & Blue Light Filter",
  "version": "1.0.0",
  "description": "Make the web less addictive and easier on your eyes. Turn websites grayscale, reduce blue light, and minimize visual distractions.",
  "permissions": [
    "storage",
    "alarms",
    "activeTab",
    "contextMenus",
    "tabs"
  ],
  "background": {
    "service_worker": "background.js",
    "scripts": [
      "background.js"
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "monotone@vigneshrapaka.com",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "action": {
    "default_icon": {
      "16": "assets/icon16.png",
      "48": "assets/icon48.png",
      "128": "assets/icon128.png"
    },
    "default_title": "Monotone Settings",
    "default_popup": "popup.html"
  },
  "icons": {
    "16": "assets/icon16.png",
    "48": "assets/icon48.png",
    "128": "assets/icon128.png"
  },
  "commands": {
    "toggle-grayscale": {
      "suggested_key": {
        "default": "Alt+G",
        "mac": "MacCtrl+G"
      },
      "description": "Toggle Grayscale Mode"
    }
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_start"
    }
  ]
}