Hi, they are not using a web server and plugin with their Docker implementation currently. They are using a different software for orchestration that sets everything up for them. They do use a IHS and Plugin for their non Docker related deployed Liberty instances using Dynamic Routing, Health Management and Auto Scaling, in some instances.
If you are interested with Docker and Liberty with IHS and the Plugin, I did present a lab at Interconnect this year. You can find the material here: https://ibm.box.com/s/jqxkrm4fqjm3sxgja0fhbpxscz5bjsz3 . The part about Bluemix and containers needs to be updated since Kubernetes is in use, but the local examples of deploying Docker containers with Liberty and have it use Dynamic Routing and Auto Scaling is still valid.
Brian