My question might not be magento specific, but I'm curious, as I couldn't find the answer elsewhere (or failed to find the correct terms).
When I use Google Pagespeed on a magento 2 website with a template based on the basic one (or Luma), it says :
Remove unused CSS
But the code for the link to this CSS is :
<link rel="stylesheet" type="text/css" media="screen and (min-width: 768px)" href="https://www.magento2-website.com/static/versionxxxx/frontend/Template/base/fr_FR/css/styles-l.min.css" />
So it's supposed to be only use if width is more than 768px.
Any idea why Pagespeed thinks it have to be taken account ?