F44 Incorrect Tabindex Values

The example code for F44 details a ul element, for which incorrect tabindex attribute values have been specified. I believe the code should instead present an ol element. Since incorrect tabindex values are considered a failure here, as they lead to incorrect navigation of the correct sequence of book chapters in the example, the code must have an ol element. By nature, an unordered list has no meaningful sequence, and therefore the tabindex values should be of no consequence, whereas an ordered list does have meaningful sequence, thus attaching importance to the correct tabindex values. Proposed change: change example code to detail ol element instead of ul element.