Examine source code of Web Page Refresher

{
  "manifest_version": 2,
  "name": "Web Page Refresher",
  "version": "1.0",
  "description": "A simple extension to refresh web pages.",
  "icons": {
    "48": "icons/icon.png"
  },
  "browser_action": {
    "default_icon": "icons/icon.png",
    "default_popup": "popup.html"
  },
  "permissions": [
    "tabs"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{410de883-6042-434e-a51f-8306ff160556}"
    }
  }
}