At revision 9, I've added a "bleeding" section to all the backports repositories (alongside the usual main, universe, etc).
This is an area where I'll experiment with beta or bleeding technology. This may include:
- Smart Package Manager
- CVS Snapshots of Firefox, etc.
- Wine snapshots
- Not-so-stable enhancements, like enhanced features from the upstream release (i.e. upgrade-notifier, simple synaptic from Hoary).
The main difference between bleeding and -staging, is that staging stuff is going to go into the stable branch for sure, while the bleeding stuff is more experimentally natured.
So, common sense says that the stability won't be a big part of the bleeding branch, so don't add it to your sources.list unless you're really sure of what you're doing!