Inside Macintosh was great documentation (I’d argue that the second generation in the 1990s, split up by topics, was the peak of Apple’s documentation writing), but I would not classify it as “Internals” in the sense of how a 1970s computer would be documented. There was a clearly delineated API boundary beyond which it was discouraged to venture.

Yes, Apple was/is mostly about computing as an appliance (realized fully in iOS), but there was occasional dabbling with User computing, especially with HyperCard, and to some extent with AppleScript. It seems that ultimately these did not have enough uptake to warrant investing more into them.

The more time I spend getting elderly people’s entertainment systems back into a state where they can watch their 3 favorite TV channels in peace without getting lured into the paywalls of their Android TVs or cable providers, the more sympathetic I’m getting to the “appliance” view.