The 10 airports for US pre-clearance trials are:
Brussels Airport, Belgium;
Punta Cana Airport, Dominican Republic;
Narita International Airport, Japan;
Amsterdam Airport Schipol, Netherlands;
Oslo Airport, Norway;
Madrid-Barajas Airport, Spain;
Stockholm Arlanda Airport, Sweden;
Istanbul Ataturk Airport, Turkey; and
London Heathrow Airport and
Manchester Airport, United Kingdom.
As you can see it not only EU airports