Universal-ctags is a replacement for the Exuberant-ctags tool.
Universal-ctags has advantages over Exuberant-ctags in that it is still maintained.
For these reasons the latest version of Zeus uses Universal-ctags as it's ctags tagger.
The code for Universal-ctags can be found here: https://github.com/universal-ctags/ctags
At any time you can update that tagger by building it from the github source code link from above, rename the executable produced to xtags.exe can putting that new tagger in the Zeus installation folder.