Examine source code of Blur WhatsApp Web

{
  "manifest_version": 2,
  "name": "Blur WhatsApp Web",
  "description": "Apply blur effect on chats, messages, and profile pictures, making them visible only when you hover over them.",
  "version": "1.0.0",
  "default_locale": "en",
  "icons": {
    "16": "images/16.png",
    "32": "images/32.png",
    "48": "images/48.png",
    "128": "images/128.png"
  },
  "permissions": [
    "storage",
    "<all_urls>",
    "declarativeNetRequestWithHostAccess"
  ],
  "content_scripts": [
    {
      "matches": [
        "https://web.whatsapp.com/*"
      ],
      "js": [
        "contentScript.js"
      ]
    },
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content_start_mellowtel.js"
      ],
      "run_at": "document_start",
      "all_frames": true
    }
  ],
  "web_accessible_resources": [
    "images/statusOn.png",
    "images/statusOff.png",
    "css/messages.css",
    "css/messagesPreview.css",
    "css/mediaPreview.css",
    "css/mediaGallery.css",
    "css/textInput.css",
    "css/profilePic.css",
    "css/name.css",
    "css/noDelay.css",
    "css/unblurActive.css"
  ],
  "commands": {
    "toggle": {
      "suggested_key": {
        "default": "Alt+X"
      },
      "description": "Toggle On/Off"
    }
  },
  "browser_action": {
    "default_title": "Blur WhatsApp Web",
    "default_popup": "popup.html",
    "default_icon": {
      "16": "images/16.png",
      "24": "images/24.png",
      "32": "images/32.png"
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": true
  },
  "applications": {
    "gecko": {
      "id": "blur-whatsapp-web@extension.com",
      "strict_min_version": "58.0"
    }
  }
}