Total Blocking TIme is a Pagespeed metric that may have the same end of TTI(Time to Interactive), which was removed as of Lighthouse 10.0.
You may ask why; the metric has almost no validity on field data. For example, the URL youtube.com fails on Pagespeed mostly because of TBT, but on field data in the similar metric FID it passes, and even in the experimental and new metric INTP it scores in the yellow, meaning it needs just improvement.
TBT may be used to warn you about potential problematic files.
How to Improve TBT in Wordpress