The manual and dev manual automated builds are failing on master, but I can't reproduce on any of my local builds and the output is now very terse, so it's not obvious to me how to debug. There were some updates recently to the manual make process, which could be related.
I'd move to re-introduce more of the tex output by default when building the manuals - this clutters the log but overall I'd say would save time (and might be the most efficient way to debug this current issue).
