To install this overlay, add URL to your /etc/layman.cfg:
	https://blshadow.org.ru/gitlab/gentoo-overlays/smoverlay/raw/master/metadata/smoverlay.xml
Example:
	overlays  : http://www.gentoo.org/proj/en/overlays/repositories.xml
		    https://another-repo.tld/repo.xml
		    https://blshadow.org.ru/gitlab/gentoo-overlays/smoverlay/raw/master/metadata/smoverlay.xml
Then you need to add repo by layman:
	layman -a smoverlay