For a variety of unfortunate reasons, it had to be installed that
way to meet the requirements of the release.
The daemon does basically nothing until a user activates Dedicated
Network Builds.
So, yes, it is by design and, yes, we consider it to be a bug and
am working towards a different solution in a future release. No
need to file a bug on this particular issue.
If you want to permanently disable it:
sudo launchctl unload -w /System/Library/LaunchDaemons/
com.apple.dnbobserver.plist
Just remember to re-enable it if you want to use DNB:
sudo launchctl load -w /System/Library/LaunchDaemons/
com.apple.dnbobserver.plist
b.bum