So, what caused all this extra work that slowed down
page loads? The majority of the work came from
JavaScript that the Brave browser injected into every
page to help its adblocker. Specifically, it was the
cosmetic filter — a component responsible for adjusting
page layouts to correct for breakages caused by
adblocking. Brave’s developers didn’t need to work on
the script to improve its performance; they needed to
delete it.
