public StructDef structDef(String name) {
        StructDef ret = structDefs.get(name);
        if (ret != null) return ret;
        ret = new StructDef(name, this);
        structDefs.put(name, ret);
        return ret;
    }
A value which may be either an url or a path.
config/src/main/java/com/yahoo/vespa/config/ConfigDefinition.java