From The Introduction:
Avionics Displays CD is intended as a tool for the avionics equipment designer, refurbisher, modifier, installer and anyone else who deals with instrumentation for the flight deck and cabin. You'll find it a source of standards, practices and techniques widely used throughout the industry. Equivalent to a 425-page printed book, its contents are easily accessed by hyperlinks and searching.

The legal aspect is covered in “Display Standards”. It contains the full text of two important Advisory Circulars produced by the FAA, with detailed guidance on designing and mplementing displays.

If you’re producing a new piece of equipment or reworking an instrument panel, be sure to look at the chapter “Panel Abbreviations.” It contains hundreds of recommended abbreviations for switches, buttons, controls, displays and most other control functions.

The subject of displays has had a long and sometimes controversial history. Because there is no reliable account, here is our guess. It probably began when a pilot first tied a piece of yarn to a wing strut. When he flew in a crosswind, and crabbed the airplane to make good a track over the ground, the yarn indicated this by not pointing straight back. It took up an angle with respect to the track of the airplane.