Cqrs.Command.internal_field

You're seeing just the macro internal_field, go back to Cqrs.Command module for more information.
Link to this macro

internal_field(name, type, opts \\ [])

View Source (macro)

Specs

internal_field(name :: atom(), type :: atom(), keyword()) :: any()

The same as field/3 but sets the option internal to true.

This helps with readability of commands with a large number of fields.