association-1.0.0-alpha2/config/schema/association.block.schema.yml

block.settings.association_block:
  type: block_settings
  label: 'Entity Association block'
  mapping:
    view_mode:
      type: string
      label: 'Display view mode'
    bundles:
      type: sequence
      label: 'Allowed association types'
      sequence:
        type: string
    menu_display:
      type: string
      label: 'Menu display option'
    menu_display_field:
      type: string
      label: Field to determine menu visibility