libavahi-client3 0.7-4ubuntu5 (amd64 binary) in ubuntu focal

 Avahi is a fully LGPL framework for Multicast DNS Service Discovery.
 It allows programs to publish and discover services and hosts
 running on a local network with no specific configuration. For
 example you can plug into a network and instantly find printers to
 print to, files to look at and people to talk to.
 .
 This package contains the library for Avahi's C API which allows you
 to integrate mDNS/DNS-SD functionality into your application.