5.0.3 API REST CustomFields : how to fetch them?

Hi

I’ve created (using the webapp) a custom field applied to Users. I can see the field in the form of User.

But when i GET /REST/2.0/customfields, it returns 0 items.

Any idea why i can’t get customfields ? Note that my API Key is owned by the user i used to create it.

The user has full permission. I can see “SeeCustomField” in permissions.

Does the parameter query is mandatory for the endpoint customfields ? Any example ?

Thank you