The original DNS Servers given by a Ubuntu Mate 18.04 installation?

& Of Curse an ENORMOUS hallow to the Community , it`s been a vile....... upside_down_face: ....

& I just made a system problem for my self again......
This time I changed the "DNS Servers" without writing down what the originals were.....
So the only ting I will bother you with this time is:
- What is the original DNS Servers given in an UbuntuMate 18.04 installation ???

The way I understand it, unless you specifically change your DNS settings, the default server is your ISP.

AFAIK there are no default settings for a DNS server in Ubuntu. The default is DHCP, i.e. automatic option for an IP address. If your option is not static/manual, but DHCP, and your DHCP option is not Address only all you have to do is to reboot.
Otherwise you can configure public Google DNS ( server.