Redundant <path> element inside an svg file

Question

Thw following two SVG markups render identically:

<svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24">
      <path style={inputAdornmentIcon} d="M12 12c2.21 0 4-1.79 4-4s-1.79-4-4-4-4 1.79-4 4 1.79 4 4 4zm0 2c-2.67 0-8 1.34-8 4v2h16v-2c0-2.66-5.33-4-8-4z"/>
      <path d="M0 0h24v24H0z" fill="none"/>
    </svg>

<svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24">
      <path style={inputAdornmentIcon} d="M12 12c2.21 0 4-1.79 4-4s-1.79-4-4-4-4 1.79-4 4 1.79 4 4 4zm0 2c-2.67 0-8 1.34-8 4v2h16v-2c0-2.66-5.33-4-8-4z"/>
    </svg>

Any idea what the second path element (<path d="M0 0h24v24H0z" fill="none"/>) in the first version actually does?

Answer 1

The extra path in your code is a a rectangle that covers all the svg canvas. As I've commented Google's icons are always using an extra rectangle like this for a background, but the rectangle is coming first. It's always a good idea to remove redundant elements and to simplify the markup.