Examine source code of Grayscale Webpages

{
  "name": "Grayscale Webpages",
  "version": "1.14",
  "description": "Applies a grayscale filter to all webpages. Use Alt+G to toggle.",
  "manifest_version": 3,
  "permissions": [
    "storage",
    "scripting",
    "tabs",
    "alarms",
    "notifications"
  ],
  "host_permissions": [
    "<all_urls>"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "grayscale-webpages@4040940.xyz",
      "strict_min_version": "142.0",
      "data_collection_permissions": {
        "required": [
          "browsingActivity",
          "websiteContent",
          "websiteActivity"
        ],
        "optional": [
          "technicalAndInteraction"
        ]
      }
    }
  },
  "action": {
    "default_popup": "popup.html",
    "default_icon": "icon_on.png"
  },
  "icons": {
    "16": "icon_on.png",
    "48": "icon_on.png",
    "128": "icon_on.png"
  },
  "commands": {
    "toggle-grayscale": {
      "suggested_key": {
        "default": "Alt+G"
      },
      "description": "Toggle Grayscale"
    }
  },
  "web_accessible_resources": [
    {
      "resources": [
        "content.css",
        "icon_on.png",
        "icon_off.png"
      ],
      "matches": [
        "<all_urls>"
      ]
    }
  ]
}