The Validation Server is responsible for exposing the management capabilities necessary to support evaluation of attribute rules. This includes batch calculation and validation rules.
The validation server is tied to the published feature service; it will share configurations (for example, SOC count and time outs) with the feature service (where SOC count defaults to min 1, max 2). Unlike ArcMap, ArcGIS Pro doesn't have a way to change these configurations at publishing time from the UI.
Both configurations can be changed from the Server Manager which only admins can access and modify.
JSON Response Syntax
"name" : "Validation Server",
"type" : "Map Server Extension",