DynamicSupervisor.init

You're seeing just the callback init, go back to DynamicSupervisor module for more information.

init(init_arg)

init(init_arg :: term()) :: {:ok, sup_flags()} | :ignore

Callback invoked to start the supervisor and during hot code upgrades.

Developers typically invoke DynamicSupervisor.init/1 at the end of their init callback to return the proper supervision flags.