unknown device

I received a notifiation on my phone on Sunday night at 8:33 pm stating the following:

A device called Generic Brand Vendor: Intel Corporate just connected to your home network for the first time.  Set up in Xfinity xFi at https://internet.xfinity.com/devices.  

Then last night at 4:00 in the morning I received this notification on my phone:

A device called ARRIS Set-Top Box just connected to your home network for the first time.  Set up in Xfinity xFi at https://internet.xfinity.com/devices.

What are these items?

I made NO changes to my items that are connected.  

Were these generated somehow by Comcast?