Examine source code of Age Calculator Fun

{
  "manifest_version": 2,
  "name": "Age Calculator Fun",
  "version": "1.0",
  "description": "Users can input their date of birth and current date and the application calculates their age in years, months, and days.",
  "permissions": [],
  "browser_action": {
    "default_popup": "game.html",
    "default_icon": {
      "128": "images/agee-logo.png"
    }
  },
  "icons": {
    "128": "images/agee-logo.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{57a063bc-1039-48f1-9503-7b35be420d2e}"
    }
  }
}