Examine source code of Better ctrl+c

{
  "manifest_version": 2,
  "name": "Better ctrl+c",
  "version": "1.0",
  "description": "Zapisuje historię skopiowanego tekstu i pozwala ją wyświetlić w schowku.",
  "permissions": [
    "storage",
    "activeTab",
    "clipboardRead"
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": "icon128.png"
  },
  "commands": {
    "save_clipboard": {
      "suggested_key": {
        "default": "Ctrl+C"
      },
      "description": "Zapisuje skopiowany tekst do schowka."
    }
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_start"
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{b597b60d-e6cb-4eab-b5e2-3e07f0636f33}"
    }
  }
}