/var/db/repos/gentoo/metadata/md5-cache

 is Article description::a metadata cache directory distributed with the official Gentoo repository and used by Portage if  is disabled in  (which is the default). For more information please see this forum thread.


 * With versions of Portage >=2.1.5_rc6 there is never any need to run emerge --metadata as long as the user has not enabled FEATURES="metadata-transfer" in make.conf. When metadata-transfer is disabled, metadata cache from the /var/db/repos/gentoo/metadata/md5-cache/ directory will be used directly. Run man make.conf to learn more about metadata-transfer. (see Project:Portage/FAQ)

This cache is generated by  utility (see Egencache), or   command (see Pkgcore).