Examine source code of Simple Calendar Basic

{
  "manifest_version": 2,
  "name": "Simple Calendar Basic",
  "version": "1.0",
  "description": "Create a calendar that displays the current month and year, and allows the user to navigate to previous and next months. Also, it allows the user to jump to a specific month and year. The calendar should also highlight the current date.",
  "permissions": [],
  "browser_action": {
    "default_popup": "game.html",
    "default_icon": {
      "128": "images/carlan-logo.png"
    }
  },
  "icons": {
    "128": "images/carlan-logo.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{d4d3d8b3-87e2-4d40-878c-76404be7a9d4}"
    }
  }
}