I was wondering if there is any tool that shows changed flags of recently emerged packages? I missed to use --ask -v while using emerge and I lost the verbose details. I have checked the /var/log/emerge.log and there aren't any useful information that I need.
To see recently emerged packages, you can emerge
app-portage/elogv. However, you must keep a log of emerged packages. You should have
PORTAGE_ELOG_CLASSES="info warn error log" PORTAGE_ELOG_SYSTEM="save"
make.conf. After running
elogv you will see a list of emerged packages in a date descending order and see the install log actions of each package, along with any warnings or user notices.
Regarding the changed USE flags, I'm not aware of something that keeps track of them.