If you do the following command in browser console:

$x('name(//h2)')

It returns 'H2' in Firefox and 'h2' in Chrome.

As a result, the use of name() = 'img' in Behat xpath does not give consistent results across browsers in all cases. This only has an effect if it's trying to find a link containing an image with alt text where the image does not have the 'icon' CSS class.

I searched and only found those two usages.