ui_suite_bootstrap.layouts.yml

bootstrap_grid_row_1:
  label: "Grid row (1 col) [Bootstrap]"
  path: templates
  template: layout--grid
  class: '\Drupal\layout_options\Plugin\Layout\LayoutOptions'
  category: "Columns: 1"
  default_region: main
  icon_map:
    - [main]
  regions:
    main:
      label: Main

bootstrap_grid_row_2:
  label: "Grid row (2 cols) [Bootstrap]"
  path: templates
  template: layout--grid
  class: '\Drupal\layout_options\Plugin\Layout\LayoutOptions'
  category: "Columns: 2"
  default_region: main
  icon_map:
    - [main, second]
  regions:
    main:
      label: Main
    second:
      label: Second

bootstrap_grid_row_3:
  label: "Grid row (3 cols) [Bootstrap]"
  path: templates
  template: layout--grid
  class: '\Drupal\layout_options\Plugin\Layout\LayoutOptions'
  category: "Columns: 3"
  default_region: main
  icon_map:
    - [main, second, third]
  regions:
    main:
      label: Main
    second:
      label: Second
    third:
      label: Third

bootstrap_grid_row_4:
  label: "Grid row (4 cols) [Bootstrap]"
  path: templates
  template: layout--grid
  class: '\Drupal\layout_options\Plugin\Layout\LayoutOptions'
  category: "Columns: 4"
  default_region: main
  icon_map:
    - [main, second, third, fourth]
  regions:
    main:
      label: Main
    second:
      label: Second
    third:
      label: Third
    fourth:
      label: Fourth