Examine source code of Fill Me Up

{
  "description": "AutoFills content to Page",
  "manifest_version": 3,
  "name": "Fill Me Up",
  "version": "1.0",
  "icons": {
    "32": "Icons/Frame 25.png"
  },
  "permissions": [
    "activeTab",
    "scripting",
    "storage"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "fillmeup@example.com",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "commands": {
    "insert-data": {
      "suggested_key": {
        "default": "Alt+A",
        "mac": "Alt+A"
      },
      "description": "Insert Fill Me Up Data"
    }
  },
  "action": {
    "default_title": "Fill Me Up",
    "default_icon": "Icons/Frame 25.png",
    "default_popup": "popup/index.html"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content_scripts/insert.js"
      ]
    }
  ]
}