documentation/extensions/odoo_theme/static/scss/_utilities_extended.scss

// Extend Utilities
$utilities: () !default;
$utilities: map-merge(
  $utilities,
  (
    "font-weight": map-merge(
      map-get($utilities, "font-weight"),
      (
        values: map-merge(
            map-get(map-get($utilities, "font-weight"), "values"),
            ("medium" : $o-font-weight-medium)
        ),
      ),
    ),
  )
);