rsync changelog

[axxackall]

What is the official way (possibly without any GUI - I need it for scripting) to know what's changed in my portage tree right after I did emerge rsync?

I want to know, which ebuilds has got new versions (emerge -up world doesn't work for packages I didn't install yet).

Besides new versions, I want to know about such updates as new files in cat/pack/files and in ebuild scripts (sometimes ebuilds are changed without bumping the version).

I've tried to use the output of emerge rsync but it's not really informative. Besides, I wonder if ther is such way as an official one.