Interestingly enough I can't find our own documentation on this topic but take a look here, for example:
- Tableau Doesn’t Have to Tear Us Apart - Alight Analytics » Alight Analytics
For columns, if the renamed/deleted field is not used by the viz - it is simply removed from the datasource. If it is used (directly or in calculation) we mark it (red pill or red bang).
For tables it's a bit more complex but you'll have a chance to go on Data Source tab where unavailable table will be highlighted and you can replace it with proper table.
Do you have a more specific scenario in mind?
I was searching the documentation, but couldn't find anything either.
This articles are great to help me, explaining this.