Missing settings in API

If we compare the Gitlab Admin/settings page with all of the options that can be configured vs the API documentation at https://docs.gitlab.com/ee/api/settings.html, many of the settings are missing. Example appearance

Zendesk link: https://gitlab.zendesk.com/agent/tickets/51064

Initial request:

We customize a number of Gitlab’s settings under the settings and appearance menus. It appears that a number of these configuration options are not available via API.

When will all of the options under the settings and appearances menus for admins be available via API?

cc// @rymai