Hi Carlo, We'd be happy to have nik4 alongside mapnik in the Debian GIS team, but we are low on manpower, so I'd to guide you or someone else with packaging, but we are unlikely to be able to provide this package without additional contributors.
Please refer to the Debian GIS policy and related documentation for information on the packaing workflow. https://pkg-grass.alioth.debian.org/policy/ Kind Regards, Bas
