Gnome-terminal vs Ubuntu-terminal differences?

I am using Xfce4 and I have two terminals on my system. The first one is Gnome-terminal.

And the second one is Ubuntu-terminal (???) which can be started like terminal from the first one.

As one can see, they differ in interface and performance (Ubuntu terminal is more sluggish). What I do not know is whether they have any functional differences?

All checkup commands according to this question shows first terminal as gnome-terminal, and the second one as simply terminal. If this question is correct and Ubuntu uses gnome-terminal by default then why I have two? And what is the second one?

P.S. It is not xfce4-terminal, as one can suggest.