Hostnames/IPs are fetched by a simple reverse DNS lookup on joining an IRC network. IRC cloaks or “virtual hosts” are used to hide the displayed IP/hostname or to show affiliation with a certain project. Cloaks can be as simple nick@user/nick or nick@wikimedia/nick inplace of firstname.lastname@example.org.
You can get a cloak from projects you’re affiliated with like from Wikimedia, Ubuntu and others. They will provide project specific cloaks depending on level of involvement. If you’re not affiliated or don’t want one from them on libera.chat, simply join
#libera-cloak channel and request one. The bots there will automatically provide you @user/nick cloak. Bear in mind, the channel is set to
+r mode, so you need to register with
NickServ to join the channel.