"General reference" is a closing reason used from some sites, for questions that are too simple.
The "general reference" closing reason has been proposed for questions that are in some sense "too simple":
This question is too basic; it can be definitively and permanently answered by a single link to a standard internet reference source designed specifically to find that type of information.
This close reason exists on some sites. Its generalization to the rest of the network has been denied due to the risk of abuse.