Binary descriptions:

xtables-addons-common: Extensions targets and matches for iptables [tools, libs]
xtables-addons-common-dbgsym: No summary available for xtables-addons-common-dbgsym in ubuntu eoan.
xtables-addons-dkms: Extensions targets and matches for iptables
xtables-addons-source: Extensions targets and matches for iptables [modules sources]