Examine source code of wpprivacy

{
  "manifest_version": 2,
  "name": "wpprivacy",
  "description": "Blur everything on WhatsApp™ Web with one click!",
  "author": "Micael Levi L. C.",
  "version": "0.0.1",
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": true
  },
  "browser_action": {},
  "icons": {},
  "content_scripts": [
    {
      "matches": [
        "https://web.whatsapp.com/*"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{5b4ccc4d-6964-4483-afdc-4189ad202007}"
    }
  }
}