storm-1.x-dev/modules/storm_layout_builder/storm_layout_builder.layouts.yml

storm_layout_onecol:
  label: 'Storm One column'
  path: layouts/onecol_section
  template: layout--onecol
  library: storm_layout_builder/layout.base
  class: '\Drupal\storm_layout_builder\Plugin\Layout\StormLayout'
  category: 'Columns: 1'
  default_region: content
  icon_map:
    - [content]
  regions:
    content:
      label: Content

storm_layout_twocol_section:
  label: 'Storm Two column'
  path: layouts/twocol_section
  template: layout--twocol-section
  library: storm_layout_builder/layout.twocol
  class: '\Drupal\storm_layout_builder\Plugin\Layout\StormTwoColLayout'
  category: 'Columns: 2'
  default_region: first
  icon_map:
    - [first, second]
  regions:
    first:
      label: First
    second:
      label: Second

storm_layout_threecol_section:
  label: 'Storm Three column'
  path: layouts/threecol_section
  template: layout--threecol-section
  library: storm_layout_builder/layout.threecol
  class: '\Drupal\storm_layout_builder\Plugin\Layout\StormThreeColLayout'
  category: 'Columns: 3'
  default_region: second
  icon_map:
    - [first, second, third]
  regions:
    first:
      label: First
    second:
      label: Second
    third:
      label: Third

storm_layout_fourcol_section:
  label: 'Storm Four column'
  path: layouts/fourcol_section
  template: layout--fourcol-section
  library: storm_layout_builder/layout.fourcol
  class: '\Drupal\storm_layout_builder\Plugin\Layout\StormLayout'
  category: 'Columns: 4'
  default_region: first
  icon_map:
    - [first, second, third, fourth]
  regions:
    first:
      label: First
    second:
      label: Second
    third:
      label: Third
    fourth:
      label: Fourth