stat/umask is a SAP Parameter attribute which is used to control Permission umask for stat-files (Unix only) 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 .
The profile parameter stat/umask specifies with which authorization mask
statistics files are created. It can only be set on Unix systems. The
use is the same that for the command umask on Unix. Note its
documentation on your operating system.
See SAP Parameter Documentation for full SAP documentation for this profile parameter.