Minify CSS & JS
SWIS can remove excess white-space, comments, etc. from any CSS & JS on your site. While many developers are diligent about making sure the CSS & JS they include is "minified", you can easily find some that are not very efficient. It might even be your own style.css if you use a child theme, I know I don't minify my child theme style.css, not when I have tools to do it for me!.
As an example, the default Twenty Twenty theme includes a stylesheet that is 121kb. When we apply SWIS Minify to the stylesheet, it cuts it down to 89kb, which saves us 26% on just one file! Of course, SWIS will also apply GZIP compression on top of that, which takes an 89kb stylesheet down to 18kb. You're welcome :)
Okay, it sucks, but it happens. No minifier is perfect, not even the one we use. So if something breaks, and you have to add an exclusion to prevent that, give us a holler and we'll report it upstream. And if you can't figure out what's broken, give us a holler anyway, and we'll help you figure out what done it.