public String toString() {
        if (!this.hasReferences()) {
            return this.getName();
        }
        Iterator<Marker> it = this.iterator();
        Marker reference;
        StringBuilder sb = new StringBuilder(this.getName());
        sb.append(' ').append(OPEN);
        while (it.hasNext()) {
            reference = it.next();
            sb.append(reference.getName());
            if (it.hasNext()) {
                sb.append(SEP);
            }
        }
        sb.append(CLOSE);

        return sb.toString();
    }
This method is mainly used with Expression Evaluators.
slf4j-api/src/main/java/org/slf4j/helpers/BasicMarker.java