Is it possible to get the layer names as they appear in the MXD using the ArcGIS Server Admin API? I know you can get the data source names with a manifest request, e.g. http://<HOSTNAME>:6080/arcgis/admin/services/<FOLDER_NAME>/<SERVICE_NAME>.MapServer/iteminfo/manifest/manifest.json, but I'd also like to get the layer names as they appear in the MXD, but from the admin API and not actually querying the MXD or the REST endpoint of the map service. I.e. I do NOT want to have to use http://<HOSTNAME>:6080/arcgis/rest/services/<FOLDER_NAME>/<SERVICE_NAME>/MapServer to get the layer names and prefer to use the Admin API entirely for everything.
I thought I found this at one point but now I'm not able to.