How did I get a secret hat?

Question

I got a secret hat.

How can I know how did I get it?

If I go into the hat selection screen, it just says "this is a secret hat", which doesn't make much sense.

Usually secret achievements and such are secret until you get them.

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I'm not telling which hat is this because I'm not asking about how to get this secret hat, I'm asking how can I know how I did get a secret hat, once I've got it. It aims to be a general question.

Answer 1

You can't know! If you do manage to work it out though, there could be more secret hats in it for you...

All secret hat secrets will become unsecret after winterbash.

Some secret hats have been desecreted here too.