Good that this topic is being discussed again. We do have a rather basic FAQ which can not take all aspects of our site into account.
This having said there already are some Meta discussions on which sources to consult, or on the amount of research effort we need for a good question:
These discussions show that it is yet to be defined what minimal prerequisites a question needs to not be closed. In addition there is no such close reason like "General Reference".
This should by no means say that we do not expect research effort before asking. But whenever information we seek could easily be obtained by consulting any online dictionary, and whenever we do not hear of any problems the asker may have had with results of their research it is likely that we close the question as "unclear what you are asking", or "too broad".
This does not imply that every question can not be found elsewhere. In fact almost any question here could be solved within minutes with the help of some Google fu.
But we do not want to be a place people go to whenever they have a question that could not be found elsewhere. We want people to consult us first when they have a question on the finer points of the German language.
Because of that we should be very careful to list standard "references" and then excluding all question that could not be answered there. Take Wikipedia for example. We do find a lot of information on any topic including the German language there. But we may not find an answer to our specific question quickly. It is my believe that the Stack Exchange Q & A format is much better in this.
Do not overestimate the value of standard references for finding answers. Sometimes it may even be impossible to judge the value of an answer there without the knowledge of a user base like we already have here.
But please, when asking do show us what you already found out, and why you are not happy with the resources you consulted.