Permissions-Policy header is added by default to disable a method of browser-based user tracking

See D9's CR: https://www.drupal.org/node/3213197

To disable this in D7, see default.settings.php

/**
 * Add Permissions-Policy header to disable Google FLoC.
 *
 * By default, Drupal sends the 'Permissions-Policy: interest-cohort=()' header
 * to disable Google's Federated Learning of Cohorts feature, introduced in
 * Chrome 89.
 *
 * See https://en.wikipedia.org/wiki/Federated_Learning_of_Cohorts for more
 * information about FLoC.
 *
 * If you don't wish to disable FLoC in Chrome, you can set this value
 * to FALSE.
 */
# $conf['block_interest_cohort'] = TRUE;