Ticket #56600: 56224.1.patch

src/wp-content/themes/twentyten/editor-blocks.css

@@ -265 +265 @@
         font-size: 1.5em;
 }
 
+.wp-block-pullquote .block-editor-rich-text__editable {
+        color: inherit;
+}
+
 .wp-block-pullquote .wp-block-pullquote__citation {
         color: inherit;
         font-size: inherit;