@shopify/polaris-tokens/dist/spacing.map.scss

$polaris-spacing-map: (
  'spacing-none': (
    0,
  ),
  'spacing-extra-tight': (
    4px,
  ),
  'spacing-tight': (
    8px,
  ),
  'spacing-base-tight': (
    12px,
  ),
  'spacing-base': (
    16px,
  ),
  'spacing-loose': (
    20px,
  ),
  'spacing-extra-loose': (
    32px,
  ),
);