text-orientation should have an effect on ::marker, so that, for instance, you can have upright numerals in a numbered list's markers, and otherwise mixed orientation text.

ol {
  writing-mode: vertical-rl;
  text-orientation: mixed; /*the default*/
}
ol li::marker {
  text-orientation: upright;
}

Here's a test case: https://software.hixie.ch/utilities/js/live-dom-viewer/?saved=12266

Currently, all browsers fail it. I think that's a browser bug, as even though text-orientation isn't part of the set of properties that apply directly to the ::marker pseudo, it should inherit into the text inside the marker and apply there. Do we agree, or is there something somewhere in the spec that actually makes it the expected behavior?