Sometimes, when you return to examine entries in the log a few hours after they were written, many of them have vanished. How come?
logd
Found in some supplementary log files in Sierra only, and contain a UUID which may refer to main log files.
Found in supplementary log files in Sierra and High Sierra only. May contain a UUID reference to main log files.
Attached to log tracev3 files in High Sierra only. Contents and function not known.
High Sierra makes two significant changes to the unified log system, from Sierra. Here’s an evaluation of them.
The Eclectic Light Company 