Examine source code of Gofakeit

{
  "manifest_version": 2,
  "name": "Gofakeit",
  "description": "Generate fake data for testing and development",
  "version": "1.0.1",
  "icons": {
    "16": "images/icon16.png",
    "48": "images/icon48.png",
    "128": "images/icon128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "extension@gofakeit.com"
    }
  },
  "permissions": [
    "scripting",
    "activeTab",
    "contextMenus",
    "storage",
    "<all_urls>"
  ],
  "web_accessible_resources": [
    "images/full.svg"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_title": "Gofakeit",
    "default_popup": "popup.html"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "css": [
        "content-scripts/content.css"
      ],
      "js": [
        "content-scripts/content.js"
      ]
    }
  ]
}