Suggested section: user interface

[lproven]

The most pervasive UI standard across multiple platforms is IBM Common User Access:

• Wikipedia
• Common User Access - A consistent and usable human-computer interface for the SAA environments [PDF]
• IBM SAA CUA Basic Interface Design Guide [PDF]

This has influenced Windows, OS/2, KDE, Xfce, LXDE, LXQt, GNOME 2/MATE, Cinnamon, and others.

Others:

Apple Human Interface Guidelines [PDF] -- for Classic MacOS

Human Interface Guidelines -- for macOS, as in OS X.

[donbarbos]

thank you, UI Guidelines are really suitable, I think I should even highlight it as a separate subtitle. and if you want you can send PR yourself (in any case, I will get to it soon)

[lproven]

Can't promise a PR -- my day job leaves me little time -- but I am wondering how to crowd-source a summary of the IBM CUA docs for an accessibility article or series I am working on...