hostnet/atom-css-sniffer package is a companion package to the
hostnet/css-sniffer package. It provides the CSS and LESS sniffing in your Atom IDE while you type. It will show any errors in your code.
And you are done.
Make sure you have a project that has the
hostnet/css-sniffer as a composer dependency and it is installed. If you have that, opening a CSS or a LESS file should trigger the sniffer an will notify you of any errors.
Everything else is taken care of.
Good catch. Let us know what about this package looks wrong to you, and we'll investigate right away.