Option to target background images to CSS classes

To date there is no official method for using modern image formats such as WebP and AVIF in CSS without losing compatibility with browsers not supporting them. From what I know, the easiest way to get around this problem is to use scripts (e.g. this one from Modernizr) which puts class values such as “webp” and “no-webp” in the html tag depending on browser compatibility. That makes it possible to provide all browsers a compatible image using CSS like this:

.webp .container-block {
background-image: url('image.webp');
.no-webp .container-block {
background-image: url('image.jpg');

Being able to generate such CSS using Advanced backgrounds in GB would make this much easier, especially when dealing with multiple media queries. I therefore suggest an option to target CSS classes in the Advanced backgrounds menu, similarly to how it can be done with effects.