es/freelist_compactor is a SAP Parameter attribute which is used to control Use more efficient usage of EM blocks information. This is available within R/3 SAP systems depending on the version and release level.
Below is the standard documentation available and a few details of the attributes values .
You can use this parameter to make better use of the EM blocks when
activating and deactivating loads. You can reduce fragmentation in the
extended memory by using this parameter. The procedure is active in the
default setting and SAP recommends that you do not change this value
(1).
See SAP Parameter Documentation for full SAP documentation for this profile parameter.