Stop 'Battery 100% Charged' notifications

Question

I have a MBP 2018. After upgrading to Catalina, when unattended with the power adapter connected, after a while the machine will start chiming every ten seconds and displaying a '100% Charged' message on the screen.

It's driving me nuts. How can I stop it?

Weirdly, I can't find any references to this online; there are even some references to people wanting such a notification. It's a new installation, so I don't think there's any custom software doing this. Is this a new Catalina feature?