The Hatter secret hat is described below. Copied from here
Post a question at a UTC time that has 00, 15 or 30 as minutes number, i.e.
xx:30:xx. The question must have at least one upvote.
Why is it called The Hatter?
I cannot figure out the relevance of the name. From what I remember, it would make sense if it was granted at 6 PM. Is this 15/30 minute addition to deal with all possible Time Zones (15 minutes for Nepal?). In that case why is there no hat on the 45th minute -- for Nepal?