Variable: user-login-name
user-login-name is a variable defined in editfns.c.
Value
"root"
Documentation
The user's name, taken from environment variables if possible.
Probably introduced at or before Emacs version 14.
Source Code
// Defined in /usr/src/emacs/src/editfns.c
DEFVAR_LISP ("user-login-name", Vuser_login_name,
doc: /* The user's name, taken from environment variables if possible. */);