public Collection<GroupHistoryInfo> getGroupHistory() {
		return Collections.unmodifiableSet(groupHistorySet);
	}
Returns history objects that represent previously grouped vertices and their description.

@param vertex the vertex for which to check group belonging
@return history objects that represent previously grouped vertices and their description.
Ghidra/Features/FunctionGraph/src/main/java/ghidra/app/plugin/core/functiongraph/graph/FunctionGraph.java