The Jolly Good Overlay. See https://gitlab.com/jgemu.
On January 15 2023 most of the jgemu packages were merged to the ::gentoo repo and then removed from this repo. Please use the main ::gentoo repo for those packages.
To add the overlay.
eselect repository add jgemu git https://0xacab.org/orbea/jgemu.git
Or with layman.
layman -o https://0xacab.org/orbea/jgemu/raw/master/repo.xml -f -a jgemu