When building/deploying Gentoo on several machines with automated systems, it's useful to be able to override the UID/GID of the users/groups created with the ebuilds. See the URL above for the mailing list discussion.
commit 5e20773d2ef2268ba5bb5ce68e16ea07eeef820f Author: Michał Górny <mgorny@gentoo.org> AuthorDate: 2021-01-05 19:32:40 +0100 Commit: Michał Górny <mgorny@gentoo.org> CommitDate: 2021-01-09 19:02:25 +0100 acct-user.eclass: Support ACCT_USER_ID override Signed-off-by: Michał Górny <mgorny@gentoo.org> commit 3d16edacf664782db004255b67464808c257f722 Author: Michał Górny <mgorny@gentoo.org> AuthorDate: 2021-01-05 19:39:11 +0100 Commit: Michał Górny <mgorny@gentoo.org> CommitDate: 2021-01-09 19:02:27 +0100 acct-group.eclass: Support ACCT_GROUP_ID override Signed-off-by: Michał Górny <mgorny@gentoo.org>