Simon Willison’s Weblog

9th July 2024

hangout_services/thunk.js (via) It turns out Google Chrome (via Chromium) includes a default extension which makes extra services available to code running on the *.google.com domains - tweeted about today by Luca Casonato, but the code has been there in the public repo since October 2013 as far as I can tell.

It looks like it's a way to let Google Hangouts (or presumably its modern predecessors) get additional information from the browser, including the current load on the user's CPU. Update: On Hacker News a Googler confirms that the Google Meet "troubleshooting" feature uses this to review CPU utilization.

I got GPT-4o to help me figure out how to trigger it (I tried Claude 3.5 Sonnet first but it refused, saying "Doing so could potentially violate terms of service or raise security and privacy concerns"). Paste the following into your Chrome DevTools console on any Google site to see the result:

chrome.runtime.sendMessage(
  "nkeimhogjdpnpccoofpliimaahmaaome",
  { method: "cpu.getInfo" },
  (response) => {
    console.log(JSON.stringify(response, null, 2));
  },
);

I get back a response that starts like this:

{
  "value": {
    "archName": "arm64",
    "features": [],
    "modelName": "Apple M2 Max",
    "numOfProcessors": 12,
    "processors": [
      {
        "usage": {
          "idle": 26890137,
          "kernel": 5271531,
          "total": 42525857,
          "user": 10364189
        }
      }, ...

The code doesn't do anything on non-Google domains.

Luca says this - I'm inclined to agree:

This is interesting because it is a clear violation of the idea that browser vendors should not give preference to their websites over anyone elses.