[Plugin: CodeColorer] Head link query string

I ran PageSpeed on my site and one of the alerts says

Resources with a “?” in the URL are not cached by some proxy caching servers. Remove the query string and encode the parameters into the URL for the following resources

…/wp-content/plugins/codecolorer/css/codecolorer.css?ver=0.9.8

So I’m curious, is there any reason why CodeColorer needs to report its version? How common is it exactly for a proxy caching server to not cache the CSS file because of this?

If it’s not that common, then I have to question why PageSpeed is dinging my site (and presumably many others) over it.