usebb2drupal-8.x-1.0-rc1/migrations/usebb_user_contact.yml

id: usebb_user_contact
label: UseBB user contact settings
source:
  plugin: usebb_user
  constants:
    module: contact
    key: enabled
process:
  uid:
    plugin: migration
    migration: usebb_user
    source: id
  module: 'constants/module'
  key: 'constants/key'
  settings: email_show
destination:
  plugin: user_data
migration_dependencies:
  required:
    - usebb_user