It seems like the dev community has done a community facepalm when this appeared in Software Update quickly after the release of the 10.11 GM seed:
Whether it's frustration with bugs during the beta process (which should be expected) or just a desire to get back to slow down the update cycle, a lot of people want to be done with betas for a while.
It turns out there is a relatively simple way to get back to 's production software update catalog via the command line tool (drumroll please...)
Getting off of the beta update catalog and back onto production:
sudo softwareupdate --clear-catalog
softwareupdate actually has an extensive interface for managing all aspects of updating software from the App Store.
You can easily list all available updates, download or install updates, and even mark certain updates as ignored:
** Manage Updates: -l | --list List all appropriate update labels (options: --no-scan) -d | --download Download Only -e | --cancel-download Cancel a download -i | --install Install <label> ... specific updates -a | --all All appropriate updates -r | --recommended Only recommended updates --background Trigger a background scan and update operation --ignore <label> ... Ignore specific updates --reset-ignored Clear all ignored updates
I found out about a lot of this while troubleshooting missing updates during the 10.11 Developer Preview. Credit to Six Colors for helping with that.