The "unbound" DNS plugin was very rudimentary and is deprecated since
commit 4a2fe09853 ('man: mark [main].dns=unbound as deprecated') (Jun
2021).
It is part of dnssec-trigger tool, but the dnssec-trigger tool doesn't
actually use it. Instead it installs a dispatcher script
"/usr/lib/NetworkManager/dispatcher.d/01-dnssec-trigger".
Especially, since the plugin requires "/usr/libexec/dnssec-trigger-script",
which is provided by "dnssec-trigger" package on Fedora. At the same
time, the package provides the dispatcher script. So I don't this works
or anybody is using this.
https://mail.gnome.org/archives/networkmanager-list/2022-April/msg00002.html