The ImplicitModelDataForComplexProperty class is a part of the Logback configuration system and is used to hold the data needed to set a complex property on a logback component. It is typically used in conjunction with the ImplicitModelAction class. Here's an example of how it might be used in a Logback configuration file:

<configuration>
    <appender name="console" class="ch.qos.logback.core.ConsoleAppender">
        <encoder>
            <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n</pattern>
        </encoder>
    </appender>
    <root level="info">
        <appender-ref ref="console"/>
        <implicitModelAction>
            <complexProperty name="property1" class="com.example.MyComplexProperty">
                <setProperty name="subproperty1" value="value1"/>
                <setProperty name="subproperty2" value="value2"/>
            </complexProperty>
        </implicitModelAction>
    </root>
</configuration>

In this example, the complexProperty element is used to define a complex property on the root element. The ImplicitModelDataForComplexProperty class is used to hold the data needed to set the property1 property on the root element, which is of class com.example.MyComplexProperty. `