Spectroscope helps you find and track potential Spectre weaknesses in a page or web app. It makes use of public research on Spectre and its mitigation, plus some of the internal data generated by the tool itself.

The tool is a Python extension for Chrome, using a proprietary data format to communicate with Chrome. It checks the resources in a page or web app to identify potentially vulnerable resources. The results are added to the DevTools "Spectroscope" panel and include security recommendations to help protect your resources from Spectre attacks.

If you are interested in the research on Spectre, you can download the publicly available research paper and the corresponding slides from Google.