The former function of the variable was deprecated in
http://www.openoffice.org/servlets/ReadMsg?list=allfeatures&msgNo=3581

Not back with new behaviour:
global string variable: gPrivateEnvironmentLocation

get's set if you have the following entry in your testtoolrc:
[PrivateEnvironment]
Type=PATH
Current=.

which enables you a path selection in the testtool settings;
If it is set other than empty and '.' the global variable contains this path.

The use is to have a global path available that can be used in testscripts,
beside the basepath setting from the testtool.

Default, after using the path dialog in testtool, is that there is no path
character at the end.