This breaks the announcement of <select> lists with size>=2 E.g. (paste this "data-url" into your address bar):

data:text/html,<p>Before</p><select size="2"><option>Frogs</option><option>Birds</option></select><p>after</p>

When arrowing down through the document in browse mode, Normally NVDA would say:

before
list clickable frogs
after

But now it says:

Before
list clickable Frogs
out of list
after

I believe that the rule to return single line in getPresentationCategory should still mention list, but only if it does not have the readonly or editable states.
So rather than removing that rule completely, also check to ensure it does not have the editable state.
In the end:

• lists with no readonly or editable state (E.g. select with size>=2) should be singleline
• ul lists in a contenteditable should be container
• read-only ul lists should be container

edits
Improved formatting, explained data url.

Got it will try to implement that too.

@awalvie: Have you made the requested changes yet?

@awalvie any updates on this?

As there are edge cases this pr does not successfully cover, and because Google has filed a bug against Chrome to probably address this in Chrome: https://crbug.com/1087551
We will close this pr.