Custom-logo / SVG / dimensions ?

Did I fault if logo.SVG HTML output has no dimensions?

SVG support:

function svg_upload ($svg_mime) {
    $svg_mime['svg'] = 'image/svg+xml';
    return $svg_mime;
}
add_filter( 'upload_mimes', 'svg_upload' );

Custom logo support:

add_theme_support( 'custom-logo', array(
  'height' => 38,
  'width' => 162,
  'flex-height' => true,
  'flex-width' => true,
 ));

Im using customizer to upload logo. Why are dimensions ignored? If I take a look to other sites that use logo.SVG, <img> include dimensions.

Thanks you