(adsbygoogle = window.adsbygoogle || []).push({}); Can someone explain what the SHSH file on Cydia is? It's always there when I open Cydia and I just want to know what it is.

The SHSH represents a signature needed to downgrade to that firmware. Without it, you cannot downgrade to that firmware

Always save SHSH blobs whenever you jailbreak, otherwise you will not be able to downgrade to the firmware you are on. It is a foolish decision to not save them.

So you can restore safely without updating. It's not saved on you're iPod it's saved on Cydia's Local servers. If you you're self want to save you're SHSH Blobs then use the tiny umbrella tool.