[css-pseudo-4] Specify ::marker::marker as invalid, define that display loses its 'list-item'. w3c#1793 (comment)

Author: fantasai

css-pseudo-4/Overview.bs

@@ -848,9 +848,13 @@ List Markers: the ''::marker'' pseudo-element</h3>
   Only a limited set of properties can be used on the ''::marker'' pseudo-element.
   This list is defined in [[css-lists-3#marker-properties]].
 
-  Note: The  ''::before::marker'' or ''::after::marker'' selectors
+  The  ''::before::marker'' or ''::after::marker'' selectors
+  are valid and
   can be used to represent the [=marker boxes=]
   of ''::before'' or ''::after'' pseudo-elements that happen to be [=list items=].
+  However ''::marker::marker'' is invalid,
+  and the computed value of 'display' on ''::marker''
+  loses its ''display/list-item'' aspect.
 
 <h3 id="placeholder-pseudo">
 Placeholder Input: the ''::placeholder'' pseudo-element</h3>