Maintainers for libakonadi-kabc4 are Debian/Kubuntu Qt/KDE Maintainers <debian-qt-kde@lists.debian.org>.
You may want to refer to the following packages that are part of the same source: kdepimlibs-kio-plugins, kdepimlibs5-dev, libakonadi-calendar4, libakonadi-contact4, libakonadi-kcal4, libakonadi-kde4, libakonadi-kmime4, libakonadi-notes4, libakonadi-socialutils4, libakonadi-xml4, libgpgme++2v5, libkabc4, libkalarmcal2, libkblog4, libkcal4, libkcalcore4, libkcalutils4, libkholidays4, libkimap4, libkldap4, libkmbox4, libkmime4, libkontactinterface4a, libkpimidentities4, libkpimtextedit4, libkpimutils4, libkresources4, libktnef4, libkxmlrpcclient4, libmailtransport4, libmicroblog4, libqgpgme1, libsyndication4.
You might like to refer to the libakonadi-kabc4 package page, to the Package Tracking System, or to the source package src:kdepimlibs's bug page.
If you find a bug not listed here, please report it.