Search: Find Items with Layer not Assigned

This will find all Content Items where the value "Basic Information" is not present in the field that stores all assigned layers "layerSchemaIds".

-layerSchemaIds:BasicInformation

To check if a field or layer is not available you negate the value with a dash
The syntax is based on Elastic Search Boolean Operator Logic: https://www.elastic.co/guide/en/elasticsearch/reference/current/query-dsl-query-string-query.html#_boolean_operators