Examine source code of forceRefresh

{
  "manifest_version": 2,
  "name": "forceRefresh",
  "version": "1.0",
  "description": "adds forceRefresh=1 to end of url and refreshes the page",
  "icons": {
    "64": "icons/icon.png"
  },
  "permissions": [
    "<all_urls>",
    "tabs"
  ],
  "background": {
    "scripts": [
      "forceRefresh.js"
    ]
  },
  "browser_action": {
    "default_icon": {
      "64": "icons/icon.png"
    }
  }
}