a Google search usually helps
The usability here is similar to having a numerical error code to google. Unless one has seen the message before and know what it means, one has little chance to figure out that it's talking about a CSS selector.
Excellent error message inform the user as to exactly what is wrong.
The current one merely informs the user that something is wrong.
I'm not sure the additional words there add much to it, and any attempt to add "Sizzle" or "jQuery"
If you look at my ticket again i never asked for those terms to be added, but simply the term "CSS selector", which is specifically what the error message is about.
In an optimal world the error would also come with a stack tract to point out where in the code it came from, and the selector parser would, in a case of parse-fail, reparse in order to be able to provide an explanation of what it expected to see, but i'm aware those are non-trivial efforts. However making the error at least clear enough so it can be easily seen what it is about, is very trivial. :)