There used to be a "too localized" close reason.
What should we do with question which are really unlikely to be of use to any one except the OP?

E.g. consider the following question:

> https://cstheory.stackexchange.com/q/20227/

I am hesitant to close it as not research level because it is about understanding a paper.
On the other hand the issue was the OP missing a simple point while reading the paper.

I also don't see how to edit the question to make it a question useful for others.

What should we do in this and similar cases?