GTK login screen: What is IceWM doing there?

I initially installed Tumbleweed with the XFCE option back in April. Today, after the 6.4 kernel update, I noticed a new icon in the upper right-hand corner of my login screen. When I clicked it, it appears to give me the option of logging in as an XFCE session, or with IceWM. Which is nice, I guess, except… I don’t remember installing IceWM. Ever.

Is this a backup WM that’s on every Tumbleweed install, and I’ve just never noticed it before? What app install could have put it there otherwise?

IceWM is a fallback DE which is installed by default by most of linux distributions.

And very lightweight, on disk, only a bit over 4M.