Introduced in 1997, Apple System Profiler gave detailed information about a Mac’s hardware and software. Later came Gestalt, a dictionary of useful info about a Mac.
IOKit
Digging for buried treasure in the Unified log isn’t easy, but has a fine track history of bringing plenty of silver and gold. Here it’s about batteries.
Where can you look if you can’t find it in System Information? What if you need that value or setting in a script or app? Here are some suggestions.
Trying to get hardware info within an app – simple data like CPU details, logic board ID, type of internal storage – is fraught and undocumented, the victim of prolonged self-neglect.
Adds details of the sequence of screens displayed at each stage, to help diagnose boot problems.
Single-diagram summary of how a modern Mac starts up in macOS 10.12 or 10.13, from pressing the Power button to running the kernel.
How macOS gets to load a hefty kernel and over 300 extensions so quickly: it cheats with a pre-linked kernelcache. And why you don’t see extensions loading in the log.
The Eclectic Light Company 