GraphDB: Use RDF-star for edge labels in custom graph?

Question

https://graphdb.ontotext.com/documentation/standard/exploring-data.html#create-your-own-visual-graph describes the ability to create a visual graph using SPARQL queries, and for the "Edge Basics" step it says:

Edge basics: This query SELECT the ?label binding that determines the text of the edge. If empty, the edge IRI’s local name is used.

In the UI for this step, there is also the "RDFS or SKOS label" sample query, which fills:

# Note that ?edge is the edge's IRI and must be used in the query.
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
PREFIX skos: <http://www.w3.org/2004/02/skos/core#>

SELECT ?label {
    # Select either rdfs:label or skos:prefLabel as the label
    ?edge rdfs:label | skos:prefLabel ?label .
}

My question is how do I leverage this capability? More specifically, what is the edge IRI (i.e. ?edge) that is the subject of the rdfs:label statement?

Is it simply the RDF predicate in the graph, as in the following?

:someSubject :somePredicate :someObject .
:somePredicate rdfs:label "Some friendly label for every :somePredicate relation" .

Is it possible somehow to use RDF-star, as in the following?

:someSubject :somePredicate :someObject .
<<:someSubject :somePredicate :someObject>> rdfs:label "A friendly label for the particular relation between :someSubject and :someObject" .

It appears to be the former case, as I get the following result when I load the above statements and use the sample query above:

someSubject --"Some friendly label for every :somePredicate relation"--> someObject

I'm curious if there is any way to leverage RDF-star statements in order to render edge-specific labels?