libavahi-common-dev 0.7-4ubuntu7 (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 development headers for the Avahi common
 library, which is a set of common functions and definitions used by many
 of Avahis components and client applications.