libavahi-client-dev 0.8-10ubuntu1 (amd64 binary) in ubuntu mantic

 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 Avahi's C API which
 allows you to integrate mDNS/DNS-SD functionality into your application.