CMDB Sync relation overrides

Device sync has quite a mandatory configuration option about relations between SL1 devices vs Snow CIs. We have used that a lot but now struggling with some issue we noticed this "values" section.

In documentation we can see this picture:

which shows that there is part "values" and it is told that they are Additional Child Class Values. Then in example we have this

{ "cmdb_ci_db_mssql_instance": { "relations": [ { "parent": "cmdb_ci_win_server", "rel_type": "Runs on::Runs", "reverse": true } ], "values": {"sys_class_name": "snow_ci_class", "instance_name": "name"} }, "cmdb_ci_db_mssql_database": { "relations": [ { "parent": "cmdb_ci_db_mssql_instance", "rel_type": "Contains::Contained by", "reverse": false } ], "values": {"sys_class_name": "snow_ci_class", "database": "name"} }, "cmdb_ci_db_mssql_server": { "relations": [ { "parent": "cmdb_ci_win_server", "rel_type": "Runs on::Runs", "reverse": true } ], "values": {"sys_class_name": "snow_ci_class", "instance_name": "name"} } }

Not much told about those in documentation, so few questions arise:

• when do we need to use those? Seems to be optional anyway.
• what are the field names to be used here. In the example snow_ci_class seems to be coming from device attributes/field from SL1, then probably the key part is the snow field? Is that correct?