Reference

Preview

Default snippet

<<?= $level = $block->level()->or('h2') ?>>
  <?= $block->text() ?>
</<?= $level ?>>

Default blueprint

name: field.blocks.heading.name
icon: title
preview: heading
fields:
  level:
    label: field.blocks.heading.level
    type: select
    empty: false
    default: "h2"
    width: 1/6
    options:
      - h1
      - h2
      - h3
  text:
    label: field.blocks.heading.text
    type: writer
    inline: true
    width: 5/6
    placeholder: field.blocks.heading.placeholder

Default Vue Component

https://github.com/getkirby/kirby/blob/master/panel/src/components/Blocks/Types/Heading.vue