The man page for eclean refers to the old default DISTDIR of /usr/portage/distfiles (new default is /var/cache/distfiles) and old default PKGDIR of /usr/portage/packages (new default is /var/cache/binpkgs). It is harmless to leave it as is because of the way it is worded, but newer installs use the newer locations and have been for several years.
Created attachment 882301 [details, diff] fix path in man page
looks like the DISTDIR path was already changed in c6dee3ef49e122a99dd299eae4749b7188751287