Examine source code of Refresh All Tabs

{
  "manifest_version": 2,
  "name": "Refresh All Tabs",
  "version": "1.1",
  "description": "Refresh all open tabs with a single click.",
  "icons": {
    "48": "icon.png"
  },
  "permissions": [
    "tabs"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_icon": {
      "48": "icon.png"
    },
    "default_title": "Refresh All Tabs"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{c4b2403d-9803-4d39-aa36-449de0bb1c23}"
    }
  }
}