I plan to do a sync on Friday: Preparing for Humble sync 2026-03-27
Unfortunately, the best/proper way is the email notifications.
Some time before starting the sync hold, I do indeed sometimes open issues on the corresponding repo to let people know that their package is failing to build, but doing that for every single regressed package build would take a lot of time. Personally, when I see that a package has been failing to build for some time (e.g., a month), I assume it’s just been intentionally ignored.