Examine source code of Summer icon

{
  "manifest_version": 2,
  "name": "Summer icon",
  "version": "1.0",
  "description": "Summer symbols are often a combination of cheerful, bright images and a feeling of warmth and freedom.",
  "icons": {
    "48": "icon.png"
  },
  "browser_action": {
    "default_icon": "icon.png",
    "default_popup": "popup.html",
    "default_title": "Click me!"
  },
  "permissions": [
    "activeTab"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{26d3e1b7-4cba-46cd-99fe-05e2185bdea8}"
    }
  }
}