This is present on most other rmm products and we use it extensively to admin client sites.
Tunneling allows you to access other resources on the network without disrupting the machine you are tunneling through…
Example - you need to make changes to a router/printer/nas and need to access the web interface (or rdp, or ssh, or really anything.
Right now with syncro you have to access the machine remotely and open a web browser on the machine this allows others to see what you are doing and it ties up the machine while you are working on the issue.
With tunneling you can go through the machine behind the scenes and work locally (at your msp’s office) while not disrupting the client that may be using their machine.
It basically maps a remote ip and port to your local machine, so you can map port 443 at 192.168.1.1 (at the client site) to your computer port 8080. Then you just open a browser locally on your comptuer and point it to https://localhost:8080 and boom, the ui is accessed locally from your computer without having to take up a clients computer to access it.