It turns out Google Chrome ships a default, hidden extension that allows code on `*.google.com` access to private APIs, including your current CPU usage You can test it out by pasting the following into your Chrome DevTools console on any Google page: chrome.runtime.sendMessage( "nkeimhogjdpnpccoofpliimaahmaaome", { method: "cpu.getInfo" }, (response) => { console.log(JSON.stringify(response, null, 2)); }, ); More notes here: https://simonwillison.net/2024/Jul/9/hangout_servicesthunkjs/