How do I get rid of these?

[MR ZenWiz]

Please see the screenshot at
https://drive.google.com/file/d/1QTsZU0Uu3TLLqvEjvC3ab_BcA69PJ9sz/view?usp=sharing

My partner is having these obnoxious little windows pop up all over
her screen and they each have to be clicked on separately to make them
go away or even just to access what's under them.

How can I track down where they come from and disable that?

How can I prevent them from coming back (as a whole)?

The only method I can think of is:

1) close all the tabs one at a time except maybe one known good one.
2) clear all browser history (any exceptions?)
3) restart the browser from scratch.

Is there a better or more thorough way?

This is in Chrome v 89.0.4389.114 on Xubuntu 20.04.2 recently updated.

Thanks.

Mark