Untitled undefined type in Mermaid Config Schema

https://mermaid.js.org/schemas/config.schema.json#/$defs/C4DiagramConfig/properties/external_containerFontSize

This sets the font size of External Container shape for the diagram

Abstract	Extensible	Status	Identifiable	Custom Properties	Additional Properties	Access Restrictions	Defined In
Can be instantiated	No	Unknown status	Unknown identifiability	Forbidden	Allowed	none	config.schema.json*

external_containerFontSize Type

any of the following: string or number (Details)

external_containerFontSize Default Value

The default value is:

14