https://api.drupal.org/api/drupal/core%21modules%21user%21config%21schema%21user.schema.yml/11.x
user.schema.yml | Drupal API
user schemaymldrupalapi
https://www.openldap.org/lists/openldap-software/200510/msg00510.html
Re: "User Schema Load failed ...", using ppolicy.schema overlay
user schemaloadfailedusingoverlay