Glossary
What does non-destructive editing mean?
It means your edits are stored as instructions layered over the original recording, which is never overwritten. The practical consequence: any cut can be undone at any time, including one you made weeks ago, and including after you have exported.
The opposite — destructive editing — bakes each change into the audio file. That is how you end up with a recording you cannot recover after an over-aggressive noise-reduction pass.
Everything in Cast works this way. It is why Restore exists on every cut.