Front-End’s Missing Metric: The TBT Window – CSS Wizardry
csswizardry.com
The TBT Window is the FCP-to-TTI interval used to calculate Total Blocking Time. If FCP or TTI moves, TBT can change even when long tasks do not.
  • swicano@programming.devEnglish
    0·
    9 days ago

    5th paragraph, after an ad break:

    Total Blocking Time [quantifies] how unavailable the main thread is during page load.