Autosuggest: Guide doesn't explain where the recommendation comes from, no mention of HTML <datalist>

[renestalder]

Reference: https://www.accessibility-developer-guide.com/examples/widgets/autosuggest/

In other guides, I found this: https://thepaciellogroup.github.io/AT-browser-tests/test-files/datalist.html

And this: https://a11ysupport.io/tests/tech__html__datalist

But then, I didn't find a convenient counter example why not to use it.

Looking at our guide, there is a recommendation what this kind of component should do:

the WAI-ARIA Authoring Practices do not offer a section about autosuggests. [...] Besides many other requirements, we want to stress out explicitly the following: [...] Proper feedback must be given upon entering a filter ("2 suggestions available for X" or similar).

However, the guide does not state where this recommendation is coming from. Is it a combination of multiple WCAG recommendations? Is it coming from experience and tests made at Access For All? Is it coming though other forms of research?

I believe the guide should include a mention of the datalist element with a recommendation of whether to use it or not and a "why" for the recommendation made in the current guide.