Why does the PUG mixin make "xlink:href" just "href"?

Question

Pug

Can't solve the problem:
there is a pug mixin for inserting an svg icon:

mixin icon(name, w, h, cl)
  - cl = cl || ''
    svg(width=w height=h class=cl)
      use(xlink:href="img/sprite-svg.svg#" + name)

when compiling , xlink is stubbornly removed , leaving just href
Maybe someone came across? thanks in advance

Answer 1

Apparently because the namespace for the html, svg and math elements is known to the browser even without specifying them.
https://codepen.io/elijah_tr/pen/vRaWdd
+ https://www.w3.org/TR/SVG2/linking.html#XLinkRefAttrs