It looks like unzip_6.0-25.debian.tar.xz has been superseded by unzip_6.0-26.debian.tar.xz, and the former has been taken down. The ebuild will need to be updated accordingly. Reproducible: Always Steps to Reproduce: 1. sudo emerge -1 unzip Actual Results: 404s from Debian mirrors Expected Results: unzip updated
Our own mirrors should work as normal and serving their purpose (and so ebuilds typically don't get updated for dead links unless can't be mirrored). Is your GENTOO_MIRRORS set properly? If in doubt, unset it and it'll use: http://distfiles.gentoo.org/distfiles/fd/unzip_6.0-25.debian.tar.xz
(In such cases, we should usually mirror the tarball to a devspace as it won't change the manifest and so on, but it's not that important at all, given mirrors exist and will indefinitely while it is in tree.)
It's an older host I hadn't updated in a while. GENTOO_MIRRORS was set to http://mirrors.tds.net/gentoo, which I noticed had started causing problems at some point. I've switched it to https://gentoo.osuosl.org, but right now it's at some point in upgrading itself that emerge isn't working, so I can't test it just yet.
unzip-6.0_p26 was added to ::gentoo and old one will be removed eventually, so I don't think there's anything to do here.