Document the rollback to stable architecture with not just limiting to the following points.

• When rts is called?
• How the decision is taken on a table to be verified for rollback to stable?
• The flow of aborting an update
• How the on-disk pages are read into cache without affecting the cache pressure.
• Diagnostic functions or verbose messages that can be helpful for debugging.

Rollback to stable is not a "box" in the architecture guide top level diagram.  Still it should be referred to in the list of topics at the bottom of that page (arch-index.dox).  It should also be referenced from the Transactions page.