[gentoo-user] Orphan packages

[Leonid Podolny]

Hi,
I'm sure that this issue has already been discussed here, but I can't
find any such discussions.
Anyway, is there an easy way to find orphan packages, i.e. installed
packages that don't have repository behind? For example, if I used to
have a layman overlay and now I deleted it, all the packages that
belonged to that overlay are now orphans. I would like at least to get a
list of those packages.