Confusing ls -l format

[MR ZenWiz]

In Ubuntu 20.04, when I do a long listing of, say, my home directory,
I see this in the listing:

drwxr-xr-x  2 mrichter domain users   4096 Feb 11  2020 Documents

All but one of the files and directories listed show "domain" between
user and group id.

If I list with -o, both the "domain" and the group name disappear.

What is that "domain" piece?

AFAICT, it mainl prevents locate and find from working properly -
neither one can see the files in one of those domain directories.

I tried to Google for this and Google doesn't seem to understand the questions.

What does it mean and how can I find or locate around it?

Thanks.

Mark