Updated Drupal to 8.6. This goes with the following updates because it's possible...

[yaffs-website] / web / core / profiles / demo_umami / config / install / block.block.umami_search.yml

langcode: en
status: true
dependencies:
  module:
    - search
  theme:
    - umami
id: umami_search
theme: umami
region: pre_header
weight: -7
provider: null
plugin: search_form_block
settings:
  id: search_form_block
  label: Search
  provider: search
  label_display: visible
visibility: {  }