LibWeb+LibWebView+WebContent: Replace DNT with GPC by trflynn89 · Pull Request #6175 · LadybirdBrowser/ladybird

Global Privacy Control aims to be a replacement for Do Not Track. DNT
ended up not being a great solution, as it wasn't enforced by law. This
actually resulted in the DNT header serving as an extra fingerprinting
data point.

GPC is becoming enforced by law in USA states such as California and
Colorado. CA is further working on a bill which requires that browsers
implement such an opt-out preference signal (OOPS):

https://cppa.ca.gov/announcements/2025/20250911.html

This patch replaces DNT with GPC and hooks up the associated settings.