Those are global default fields
https://docs.servicenow.com/en-US/bundle/tokyo-platform-administration/page/build/applications/refer...
Field Type Description
| Class [sys_class_name] | System Class Name | If the table is extensible, a string field that indicates which child table contains the record. |
| Created [sys_created_on] | Date/Time | A time-stamp field that indicates when a record was created. |
| Created by [sys_created_by] | String | A string field that indicates the user who created the record. |
| Sys_id [sys_id] | Sys ID | The unique record identifier for the record. |
| Updates [sys_mod_count] | Integer | A numeric field that counts the number of updates for this record since record creation. |
| Updated by [sys_updated_by] | String | A string field that indicates the user who most recently updated the record. |
| Updated [sys_updated_on] | Date/Time | A time-stamp field that indicates the date and time of the most recent update. |
