Since my first email about what is happening in apps might not have been clear:
1. Me and Vibha had a lot of conversations about this, with Inputs
from Oliver, Maryana and others.
2. For now we are just having a freeform text field there, with
autocomplete for previously entered edit summaries
3. There will be guider text around the text field telling users what
it is, with pointers to concrete examples.
Hope that clears things up :)