What is the port to the right on the two USB C ports? To the left of the RJ45. (ThinkPad T480s with integrated graphics.)
Edit to add: thanks in advance!
In a bold attempt to force people to switch to new docking stations and hence abandon the old ones (where you docked the notebook via a proprietary port on the bottom of the machine), the “new” generation of docking stations had kind of a lever that was pushed into this abomination of a usb-c/thunderbolt slot. When we rolled out these new docks quite some users got confused, as you still “click” in the notebook into the new dock, but additionally have to push in this kind of new “lever”. Also, users got confused where to plug in the usb-c cable when not using the new dock 😬
https://download.lenovo.com/pccbbs/mobiles_pdf/t480s_ug_en.pdf (page 21)
According to the manual, it’s a docking station connector.
On my X1 carbon, I have a similar-looking port but it’s for the ethernet adapter.
That connector is the ethernet connection for the docking station. That provides a real ethernet connection on the dock rather than using a USB to ethernet adapter.
Using the NIC that’s on the CPU/chipset (I forget which) allows it to use the same MAC regardless of which docking station or adapter is used, simplifying management. It also means that vPro, wake on LAN etc. work - neither are generally a concern for a home user, but both can be desirable in the large enterprise/government situations these are built for.
Like some others have said, it’s a docking port of some sorts but I’ve never seen it in practice. In our company we buy the universal hybrid usb C docks and they are great. The connector has also a more useful secondary USB C port which you can use for charging if the primary port dies for some reason, saved us on numerous occasions that way so the user can work while we prepare a replacement machine.