I use double-entry accounting (with ledger-cli) for my personal finances. I recently found out that I had $40 stashed in one of my drawers, and I don't know when exactly I acquired them, or where I got them from. How should I record the journal entry for this? It certainly doesn't feel like a revenue, because the $40 have been sitting in the drawer since the day that I put them there.
The first half of the entry would be crediting my cash account. But what should be the other half of the journal entry?