https://devmanual.gentoo.org/general-concepts/manifest/ does not discuss thin manifests. In https://github.com/gentoo/gentoo/pull/4194, this has led to some confusion (and I've seen similar confusion before). Perhaps we can add something here, and discuss how the gentoo tree is different from most overlays in this regard?
commit 4523506762ffb0a46533c7168f64b4c8a3850ef8 Author: Michał Górny <mgorny@gentoo.org> Date: Tue Jan 7 06:59:58 2020 +0100 general-concepts/manifest: Include info on thick Manifests Signed-off-by: Michał Górny <mgorny@gentoo.org> Signed-off-by: Ulrich Müller <ulm@gentoo.org>