This actually happened to me last month. I had to touch code from a previous team/project I was on.

I got the call for a collaboration/consult. I forgot everything about it. Jumped in a meeting next day anyway. We pulled up the code. Everything was documented and I had a section with parameters for a "wish" feature that they actually wanted finally. I pointed it out and told them the needful to finish the feature.

Thank you past me. I'll have to buy you a drink.

Then I had a nice 5pm Scotch.