ArcGIS Pro 3.4.2: How to set the coordinate system of a particular layer to "Unknown"?

[JamalNUMAN]

ArcGIS Pro 3.4.2: How to set the coordinate system of a particular layer to "Unknown"?

For example, in the screenshot below, the “Define Projection” tool does not appear to provide an option to set the coordinate system of the layer to "Unknown."

[DanPatterson]

You can do it for a map

Use an unknown coordinate system—ArcGIS Pro | Documentation

Your previous posts and suggestions on this long standing issue

How to “clear” the coordinate system of the “Map” to get it to “unknown” in ArcGIS Pro,