A few years ago, intentionally fingerprinting or tracking your users without disclosure was spyware and unethical. Alas, here we are.

Anyway, what they're calling "spectroscopy", is a combination of extension probing and doing residue detection (looking for what extensions might leave behind in the DOM).

An ad blocker is not necessarily equipped to help since the script is embedded with the application code. Since they're targetting Chrome, switching browsers will help with the probing but not the detection part and you'll still be fingerprinted.

The only way forward is for browser vendors to offer a real privacy or incognito mode where sites are sandboxed by default. When the default profile is identical across millions of users there won't be anything unique to fingerprint.