I love this new feature, having environment variables available from the About screen!
On my computer the first 20 or so environment variables all look like this:
These don't show up when I do a SET from the command line, or in the System Environment Variables window.
I don't know if these are unique to my computer (it is from work), or they are standard but are usually filtered out by the operating system. Perhaps you could filter them out - they don't seem to be in the standard format, so it should be easy enough.
The list of environment variables is provided by Java using a system call. What variables are displayed and how they have been obtained by Java is hidden to DbVisualizer. I agree that some variables such as the ones you list looks weird. However, the list is supposed to be an overview of the variables and to find out what is available for use as variables in the SQL Commander.