Been away for ~1 year and found my vault empty, how to understand what wappened?

Hi guys, have there been any changes to the vault/ moon system over the last years? For various reasons haven't checked my vault for one year and nowI opened it and found it empty. I didn't have many moons in it but still it's a shame to see them vanished, and most importantly I want to know if my vault has somehow been hacked as it would mean that I have somehow been reckless while handling my seed phrase / vault password. Where can I check my vault address transactions to at least understand what's happened? Thanks a lot ♥️