The "Member for" (member_for) extra field on the User entity view display is deprecated in 11.5.0 and will be removed in Drupal 13.0.0. Instead, use the created field, which has been made configurable on the display.
For sites upgrading to Drupal 11.5.0 or 12.0, the "Member for" extra field will continue to be displayed as previously configured, and the created field will be set as hidden on the display. This allows existing site theming to work as expected. Manual action can then be taken to configure the created field to be displayed and the member_for extra field to be hidden.
New Drupal installations of 11.5 or 12.0 have the created already configured to be displayed but set to hidden as default, and the member_for extra field is hidden as well. This means on a new installation, no field data will be configured to be displayed on the user page. Site builders can customize the display after installation.
