I’ve only used ifconfig to view wired interfaces.
One of my least favorite Linux software tools is NetworkManager. This tool is designed to do the right thing based on non-permanent connections. Another way of saying this is that WiFi may come and go, and you might not care about wired except when WiFi is missing…typical mobile user usage. The problem is that this in part depends on whether your individual user is logged in or not at the GUI…settings may change conditions based on who logged in and when. I don’t use WiFi, but if I did, I would expect it to occasionally try to do something with my wired which I want it to stay away from. I edit my network config files directly and don’t use NetworkManager, so my experience will differ from yours.
Virtual wired network interfaces are something you don’t want removed (they are not an error). One example would be that a network based application would fail if it had nowhere to connect, so a NULL connection will be added for a failed connection to fail over to. You won’t magically get connected to where you want, but your application won’t freak out and die. Some interfaces may also be bridges between newer IPv6 standards traffic and older IPv4 standards traffic.
I have not yet examined the USB connections, but I suspect this depends on what micro-USB cable is plugged in (at least in R28.2). Earlier L4T releases did not have the “On the Go” (“OTG”) connector hot-detect used…this port was always in host mode. One had to customize to get this port to act as a device other than when in recovery mode. I believe this port (in R28.2) may have had optional features enabled to make it behave as a special device when a type-B connector is inserted (I noticed my PC saw this as a device when powering up…I have not yet investigated the nature of that new feature). I am thinking perhaps there is a virtual network interface now…I don’t know, but I doubt this is an error.