Which action is typically not performed during the combat damage step?

During the combat damage step, players do not declare attackers; this action occurs in the combat declaration step, which precedes the combat damage step.

In the combat damage step, the following occurs: players assign combat damage based on the creatures involved in the combat and how the damage is distributed among blockers and attackers. Combat damage is then dealt simultaneously, resolving the effects of that damage on the creatures and players involved. Additionally, damage calculation, necessary for determining how much damage each creature deals and receives, is resolved during this step. Therefore, the declaration of attackers is the only action that is not performed during the combat damage step.