It is inspired by (but currently is nowhere near as functional as) the legendary DVD Shrink application for Windows, with a little help from the various Linux DVD9->DVD5 guides around the internet.
The current release provides a simple interface to a number of open source command line tools which do the extract, shrinking and reauthoring.
This release is still very much experimental, and I welcome feedback - what DVDs does it work on, what doesn't work? What would make it more useful? If it doesn't work for you yet, then don't abandon it completely - check back for future versions which I hope will be more functional, reliable & attractive.