There was a nice debugzope script at the times when Zope 3 was packaged as a tarball. You could interactively dig into ZODB make your changes and commit.
Now at ZTK / egg / recipe / buildout times I was missing this. Therefore I created the recipe z3c.recipe.paster:debug.
(some code taken from grok ;-)

Add it to your buildout.cfg like this:

[debug]
recipe = z3c.recipe.paster:debug
app=app
where app is a z3c.recipe.paster:serve recipe.