Q: Logical plan

Hello, A quick question. Is the logical plan generated by the keyword "plan" is the plan before it is sent to the SQL optimizer *OR* the output plan of the optimizer?

From the online documentation ( https://www.monetdb.org/Documentation/Manuals/SQLreference/PlanSQL), this sentence "*The relational plan used in the SQL optimizer* can be obtained by prepending the query with the keyword PLAN." is not clear to me.

Thanks, Hanfeng Chen