I think most browsers have patched this out?
i didnt do super concrete tests, but at least on my machine their demo is failing to fingerprint me across private browsing/incognito sessions as they claim. Tested in firefox and edge.
Says that Firefox has a bug that prevents favicons from being loaded from cache, which inadvertently protects against this technique. They filed a bug report on it in 2020 but nothing has happened with it yet: https://bugzilla.mozilla.org/show_bug.cgi?id=1618257
Not sure about Chromium-based browsers, but the author of this paper on the technique:
https://www.ndss-symposium.org/wp-content/uploads/ndss2021_1...
Says that Firefox has a bug that prevents favicons from being loaded from cache, which inadvertently protects against this technique. They filed a bug report on it in 2020 but nothing has happened with it yet: https://bugzilla.mozilla.org/show_bug.cgi?id=1618257