I suspect the icons have to do with a non-english or reading disabilities accessibility requirement.
I'd argue it's not comparable to the 1992 standards because there's not clutter on the right due to dimming for the hotkey labels. These guidelines were written only slightly through Mac OS's colour era, with an extensive install base of monochrome Macintoshes where you could only depict dimming with hard-to-read dithering. Now that colour is ubiquitous, this gives designers the option to fade or tint UI items to make them look less distracting or to deemphasise them.
I'd argue it's not comparable to the 1992 standards because there's not clutter on the right due to dimming for the hotkey labels. These guidelines were written only slightly through Mac OS's colour era, with an extensive install base of monochrome Macintoshes where you could only depict dimming with hard-to-read dithering. Now that colour is ubiquitous, this gives designers the option to fade or tint UI items to make them look less distracting or to deemphasise them.