To opt your site out of FLoC, you need to send the Permissions Policy HTTP response header.

Permissions Policy is a new header that allows a site to control which features and APIs can be used in the browser. To opt-out, use this header:

Permissions-Policy: interest-cohort=()

If you have access to the .htaccess file on your Apache server, you can edit it with this code to set your Permissions Policy:

<IfModule mod_headers.c> Header always set Permissions-Policy: interest-cohort=() </IfModule>