WPMUDEV has a Broken Link Checker Plugin but it costs resources and won't be used all the time. Much better would be to have an online tool available which would check for Broken Links in sites.
The best place to have that feature available would be "The Hub".
It could be oriented on the integrity app which is available for MAC:
It would be great if that tool would remind to check a site at least all 6 months and of course automate could check a site in regular terms and report broken links.
This would be a great feature to have inside the HUB as it would save resources on the multisite installation and it would help to have much better site performances with less broken links.
Perhaps a combination with the already existing broken link checker and the hub would be thinkable if the broken Link checker plugin would enable itself and disable itself. But I think an online only version would be much better for performance and reducing the installed plugins.
Nice additional effect for INCSUB would be that this new feature would bind again customers to WPMUDEV :wink: