type to collapsible, provide a header label, and place its nested fields in fields:
title and internalNotes at the current level. The label can be text, localized text keyed by language code, or a function that receives i18n and t. To build the header from document data, set admin.components.Label to a component instead.
Config options
Admin options
Collapsible fields inherit the standard field admin options and add:Custom components
CollapsibleFieldClientProps for a client replacement. A custom label component changes only the section header.