Can I recover something I changed or deleted?

Every time you save a change to an asset's content, the previous version is kept. Open the asset and use History to read an earlier version or restore it. Restoring does not discard anything: the version you restored from is kept too.

Deleting is permanent. There is no trash and no undo: a deleted asset or project is gone, along with its history and its attached files. Export first if you are unsure.

This is stated plainly rather than softened, because a recovery promise that does not exist is the worst kind of thing to discover afterwards.