NServiceBus.Metrics.ServiceControl.Msmq provides native queue length reporting to ServiceControl Monitoring for endpoints running on the MSMQ transport. It does it by monitoring the endpoints' queue length and then passing that data to NServiceBus.Metrics.ServiceControl which in turn sends it to an instance of the ServiceControl.Monitoring service.
See the Setup Queue Length Metrics Reporting for the MSMQ Transport documentation for more information.
NServiceBus.Metrics.ServiceControl.Msmq requires the .NET Framework and can only be used with NServiceBus 8 and below.