Relation Manager: How to customize edit action?

public function form(Form $form): Form
    {
        return $form
            ->schema([
                Checkbox::make('allowAllExtensions')
                    ->label(__('templates.allow_all_extensions'))
                    ->live()
                    ->dehydrated(false)
                    ->afterStateUpdated(function (Set $set) {
                        $set('allowed_file_extensions', ["*"]);
                    }),
                Repeater::make('allowed_file_extensions')
                    ->hidden(fn (Get $get) => $get('allowAllExtensions') === true)
                    ->label(__('templates.allowed_file_extensions'))
                    ->hint(__('templates.allowed_file_extensions_hint'))
                    ->simple(
                        TextInput::make('extension')
                            ->string()
                            ->regex('/^([a-zA-Z0-9]+)$/u')
                            ->required(),
                    ),
            ]);
    }