Describe a named layer

Returns the description of a named layer in JSON format.

The layer name should be provided as part of the URL path after /layers/. Hierarchical names with slashes are supported (e.g., Samples/NamedLayers/SavingsNLoanFeatureLayer).

Resource dependencies: A named layer typically references a named table (see the table field, e.g. NamedTable) that provides its underlying data, and may optionally reference a named label source (namedLabelSourceRef). These referenced resources must already exist in the repository for the layer to render or describe correctly.

Authorization: Requires EXECUTE permission on the requested layer. If the caller lacks permission, the API returns 403 Forbidden; if the layer does not exist, it returns 404 Not Found. Both share the same error code (DIS-MS-1016), but the distinct HTTP status and message text make the two cases distinguishable to the caller.