drupalcampbristol/core/modules/block/block.routing.yml

block.admin_demo:
  path: '/admin/structure/block/demo/{theme}'
  defaults:
    _controller: '\Drupal\block\Controller\BlockController::demo'
    _title_callback: 'theme_handler:getName'
  requirements:
    _access_theme: 'TRUE'
    _permission: 'administer blocks'
  options:
    _admin_route: FALSE

entity.block.delete_form:
  path: '/admin/structure/block/manage/{block}/delete'
  defaults:
    _entity_form: 'block.delete'
    _title: 'Delete block'
  requirements:
    _permission: 'administer blocks'

entity.block.edit_form:
  path: '/admin/structure/block/manage/{block}'
  defaults:
    _entity_form: 'block.default'
    _title: 'Configure block'
  requirements:
    _entity_access: 'block.update'

block.admin_display:
  path: '/admin/structure/block'
  defaults:
    _controller: '\Drupal\block\Controller\BlockListController::listing'
    _title: 'Block layout'
  requirements:
    _permission: 'administer blocks'

block.admin_display_theme:
  path: 'admin/structure/block/list/{theme}'
  defaults:
    _controller: '\Drupal\block\Controller\BlockListController::listing'
    _title: 'Block layout'
  requirements:
    _access_theme: 'TRUE'
    _permission: 'administer blocks'

block.admin_library:
  path: 'admin/structure/block/library/{theme}'
  defaults:
    _controller: '\Drupal\block\Controller\BlockLibraryController::listBlocks'
    _title: 'Place block'
  requirements:
    _access_theme: 'TRUE'
    _permission: 'administer blocks'

block.admin_add:
  path: '/admin/structure/block/add/{plugin_id}/{theme}'
  defaults:
    _controller: '\Drupal\block\Controller\BlockAddController::blockAddConfigureForm'
    theme: null
    _title: 'Configure block'
  requirements:
    _permission: 'administer blocks'

block.category_autocomplete:
  path: '/block-category/autocomplete'
  defaults:
    _controller: '\Drupal\block\Controller\CategoryAutocompleteController::autocomplete'
  requirements:
    _permission: 'administer blocks'