I’m using v3.027 on a B1300, which I have set up as a Wireguard server. When I connect to it from a client, I see no notification of that fact. IIRC, earlier versions changed the image on the home (Internet) screen, specifically the VPN shield. That may have been when I was using OpenVPN in the past. That is not happening now.
How can I tell if my B1300, acting as a Wireguard server, currently has an active connection to a client?
You can ssh to the router and run the command wg to view
This misses my point. I believe the visual confirmation on the web-configuration works for OpenVPN, but not WireGuard. I am asking why the difference.
There is a client list in the wireguard server page of active clients 
The shield only changes when you are connected as a client using a GL router to a remote server, not when hosting the server.
What precisely is ‘last connected’ mean?
Time since the device was connected last.
So you will see a list of all clients that have connected to your server, and the last times they connected.
