This command "purges" the cell buffers - this essentially means the "cells" (parts of the map) that are no longer being used but are still stored in the game's memory (buffer) are removed and deleted (purged).
purgecellbuffers
PurgeCellBuffers
This is the only way the PurgeCellBuffers command can be executed.
PCB
PCB is an alias of the PurgeCellBuffers command - it has the same function but it shorter and easier to remember.