Thank you! And yes by default TeX doesn't do tracking or expansion, but the microtype [0] package does.

And I did struggle a bit with deciding how best to do the comparison to native browser rendering. I wanted it to be an apples-to-apples comparison, but also didn't want to unfairly handicap the browser by disabling something like hyphenation. It's already bad enough as is...

0: https://ctan.org/pkg/microtype