amino-1.0.x-dev/modules/amino_page_builder/amino_page_builder.layouts.yml

amino_1column:
  label: 'One column'
  category: 'Amino'
  class: '\Drupal\amino_page_builder\LayoutBase'
  template: templates/amino--one-column
  library: amino_page_builder/one-column
  default_region: content
  icon_map:
    - [content]
  regions:
    content:
      label: Content

amino_2column:
  label: 'Two column'
  category: 'Amino'
  class: '\Drupal\amino_page_builder\LayoutBase'
  template: templates/amino--two-column
  library: amino_page_builder/two-column
  default_region: first
  icon_map:
    - [first, second]
  regions:
    first:
      label: First
    second:
      label: Second

amino_3column:
  label: 'Three column'
  category: 'Amino'
  class: '\Drupal\amino_page_builder\LayoutBase'
  template: templates/amino--three-column
  library: amino_page_builder/three-column
  default_region: center
  icon_map:
    - [left, center, right]
  regions:
    left:
      label: Left
    center:
      label: Center
    right:
      label: Right