nappo - probably dotnet command missing

I know that this is a question for beginners, but I cannot find the nappo command. It's used in the Fedora packaging script for ARM 64 DotNet. I tried to google it, yum search, pkgs.org, repology and GitHub. The file where the nappo command is used is here: https://src.fedoraproject.org/rpms/dotnet6.0/blob/rawhide/f/build-arm64-bootstrap-tarball