The metadata for x11-misc/xaos lists the project's homepage as "http://matek.hu/xaos/doku.php", but that URL returns 404 (as does "http://matek.hu/xaos/"). The correct URL appears to be "https://xaos-project.github.io/". Reproducible: Always
This actually isn't in the metadata but the HOMEPAGE line in x11-misc/xaos/xaos-3.6.ebuild; the correct HOMEPAGE is already in x11-misc/xaos/xaos-4.2.1_p20210828.ebuild. This could be resolved by stabilizing the newer version and dropping the older one, or by fixing the older one.