Currently the hs_err file contains only limited OS user related information.
Just the user name is printed via output of environment variables (at least on Windows with USERNAME - output).
The enhanced output on UNIX would contain more information including uid, gid and umask .
uid : 1679 (testuser)
euid : 1679 (testuser)
gid : 25 (testgroup)
egid : 25 (testgroup)
umask: 0022 (removing ----w--w-)