Group-level Variable API is missing masked property

Problem to solve

Apparently we are missing masked property for group-level variables api. https://docs.gitlab.com/ee/api/group_level_variables.html#create-variable

Controller is implemented with https://gitlab.com/gitlab-org/gitlab-ee/commit/0481d699075ea48c67037088713689b8d66f1983

Intended users

Currently it is not possible to automate creating masked group variables via API

Further details

Secured group variables.

Proposal

It seems the property is just not exposed in the external api?

Permissions and Security

Documentation

Testing

What does success look like, and how can we measure that?

What is the type of buyer?

Links / references