- merge a package like ltrace via "emerge ltrace"
- it gets added to your world file
- now unmerge ltrace
- do an emerge --update world
- emerge puts it back
This means if you merge something just to try it and unmerged it later after you
deterimne you don't like it, etc, you have to manually remove the entry from the
world file or else it keeps putting it back... rather annoying :)
OK, fixed in 1.8.9 (final!). Entries in the world file are ignored if no
matching package is installed.