Examine source code of Receipt icon

{
  "manifest_version": 2,
  "name": "Receipt icon",
  "version": "1.0",
  "description": "Receipt icons are often designed to evoke the invoice or bill that a user receives after making a purchase.",
  "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": "{a924b24a-0619-42be-9123-7854ebc12561}"
    }
  }
}