DIR_ICMAN_ROOT is a SAP Parameter attribute which is used to control ICM root directory 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 .
Directory for Internet Communication Manager (ICM) data. This directory
contains, for example, the files for the Web administration interface of
the ICM or for the integrated ITS.
See SAP Parameter Documentation for full SAP documentation for this profile parameter.