1 <?xml version="1.0"?>

     2 <svg xmlns="http://www.w3.org/2000/svg" version="1.2"

     3       viewport-fill="yellow" baseProfile="tiny" viewBox="0 0 300 100">

     4       <desc>

     5       The viewport has a yellow background.

     6       The rectangle is  filled and covers the viewport, so the yellow 

     7        background will only show through in the "leftovers" if the 

     8        aspect ratio of the viewport differs from thatof the viewBox.

     9       </desc>

    10       <rect x="0" y="0" width="300" height="100" fill="red" fill-opacity="0.3" stroke="black"/>

    11 </svg>