Examine source code of simple code injector

{
  "manifest_version": 3,
  "name": "Code Injector Pro",
  "version": "2.0",
  "description": "Securely and quickly inject CSS and JS into webpages.",
  "browser_specific_settings": {
    "gecko": {
      "id": "code-injector@local",
      "strict_min_version": "142.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "permissions": [
    "storage",
    "scripting",
    "activeTab"
  ],
  "host_permissions": [
    "http://*/*",
    "https://*/*"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "action": {
    "default_popup": "popup.html",
    "default_icon": "icon.svg"
  },
  "content_scripts": [
    {
      "matches": [
        "http://*/*",
        "https://*/*"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_idle"
    }
  ],
  "web_accessible_resources": [
    {
      "resources": [
        "import.html",
        "import.js"
      ],
      "matches": [
        "<all_urls>"
      ]
    }
  ],
  "icons": {
    "48": "icon.svg"
  }
}