Copy multiple files using * wildcard from kubernetes container
Wildcard support was added to kubectl cp in the #72641 pull request.
It is merged but only available in Kubernetes v1.14.0. Take a look at the ChangeLog:

Notable Features:
[...]
• kubectl supports copying files with wild card
(#72641, @dixudx)

However, as stated on the issue #78854 the PR was made without proper tests and the feature is actually broken. The PR to fix the problem (#78928) is open since June, and it's not merged yet.
Although the PR to fix the feature exists, they are also considering removing the support to wildcard copy.