It needs to be the virtual "path" of a Splunk object type or type. This can be a specific object, or the parent path (relative to the root of the services namespace). So for example
data/indexes. The path is the one you'd use to enumerate the object(s) under the REST API (relative to the namespace root again).
Closest is http://www.splunk.com/base/Documentation/4.1.2/Developer/ModuleReference#EntitySelectLister is the closest, and notes that
entityPath should be a valid entity path such as
saved/searches. http://www.splunk.com/base/Documentation/4.1.2/Developer/HowToUseListers#EntityLinkLister mentions use to access objects via REST endpoints. However, the REST management API (as opposed to the query API) is not currently published though it can be browsed on https://splunkhost:8089/services
or maybe where i can find the entity "admin/distsearch-peer" .. maybe then i can try to backwards-translate some of this advanced xml.