[greatgib]

Do I understand correctly that this means that browser will have to do yet another useless request to domains or website to know the GPC status in addition with the request required to retrieve the ressources ? In addition with OPTION requests that already have to be done?

[jeroenhd]

OPTION isn't always necessary, there are ways to prevent those requests.

Also, the GPC request will probably only be sent when you enable GPC, which basically means "almost nobody".