Apparently based on Mach absolute time, log entry times are converted to wallclock times. This exposes them to the vagaries of time zones, seasonal adjustments, and periodic wallclock adjustments. Here’s how all that works, and can confuse.
LogUI
How to combine the time of interest with waypoints to reduce 100,000 log entries to just a handful, and discover what you’re looking for in the log.
The four types of log entry, all the fields they can contain, and those they are likely to include, shown in the order and colour scheme used in LogUI. Censorship and how to disable it, with a signed profile to do so.
Build 74 adds a Diagnostics Tool to analyse and catalogue diagnostics folders that are or have been a live log store, including those saved in backups.
Log entries are purged from storage according to elaborate rules explained here, for different types of log entry. How to extend time coverage in those logs, and how to get free statistics about them.
What you can learn from browsing the log, and why it’s so important in diagnosis and troubleshooting, research into macOS, and measuring performance. With a worked example.
An introduction to the Unified log used on Macs and Apple’s devices. Its goals, how logs are stored and maintained, their content, privacy protection, and tools available to access them.
How to check your Mac is booting in Full Security, and how to read its log to verify all the key steps involved in that process.
How to discover which apps were launched, which appexes were run, and life cycle events for executable bundles, and map waypoints and events in the log.
A meta-search for Apple’s patents on search, and turning the incessant log chatter of RunningBoard to our advantage in following uninstrumented apps.
The Eclectic Light Company 