Comment 2 for bug 1679765

Extrausers is a concept introduced by the libnss-extrausers package. shadow and passwd simply know nothing about it.

It simply is not a bug in the shadow package. It's a wholly un-implemented feature. It's not clear to me how this would function - after all these are supposed to be accounts 'copied from other systems' according to the package. And I'm not clear on how these would relate to ldap, for instance.

So if you are interested in using passwd or usermod for these, I would recommend opening a discussion at either (or both) github.com/shadow-maint/shadow/issues, or probably better at the libnss-extrausers package.