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/
There are more options than GrapheneOS with broader device support, such as Calyx or LineageOS.
But if you use Android already, you can start by using F-Droid (or others) to install apps to find FOSS replacements for apps you use.