A fling is a pet project from VMware engineers. The URL is labs.vmware.com. There is a great collection of tools that I have used in the past such as the autodeploy gui for example.
What is the Host Client Fling:
Step 1: Download the .vib from labs.vmware.com.
Step 2: Upload the vib (package) to your esxi host. Once you do that, install it with the esxcli command.
Step 3: Launch your favorite browser and connect to your esxi host via https://ip_of_server/ui. The fully qualified named of the esxi host can be used as well. DON'T forget /ui at the end of the url.
What follows is a few captures to show you some of the capabilities of this fling.