Describe named layers

Returns descriptions for the specified named layers. Each entry in the response contains the layer name and either the layer description or an error message if the layer could not be found.

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 a layer to render or describe correctly.

Authorization: Requires EXECUTE permission on each requested layer. For any layer where the caller lacks EXECUTE permission (or which does not exist), the corresponding entry contains an errorMessage instead of a layer description; the overall response is still 200 OK.