[NavigationTiming] What's new and implemented in Nav Timing 2?

Navigation Timing 2 contains the following new features:
[[

  * the definition of Performance interface was moved to
    [[PERFORMANCE-TIMELINE]];
  * support for [[PERFORMANCE-TIMELINE]];
  * support for [[HR-TIME]];
  * timing information for link negotiation
    <http://w3c.github.io/navigation-timing/#widl-PerformanceNavigationTiming-linkNegotiationStart>;
  * the number of redirects
    <http://w3c.github.io/navigation-timing/#widl-PerformanceNavigationTiming-redirectCount>
    since the last non-redirect navigation;
  * protocol
    <http://w3c.github.io/navigation-timing/#widl-PerformanceNavigationTiming-linkNegotiationStart>
    information;
  * transfer
    <http://w3c.github.io/navigation-timing/#widl-PerformanceNavigationTiming-transferSize>,
    encoded body
    <http://w3c.github.io/navigation-timing/#widl-PerformanceNavigationTiming-encodedBodySize>
    and decoded body
    <http://w3c.github.io/navigation-timing/#widl-PerformanceNavigationTiming-decodedBodySize>
    size information;
  * support for prerender <http://microformats.org/wiki/rel-prerender>
    navigation [[prerender]].
  * the domLoading
    <http://w3c.github.io/navigation-timing/#widl-PerformanceNavigationTiming-domLoading>
    attribute is deprecated.**
  * the secureConnectionStart
    <http://w3c.github.io/navigation-timing/#widl-PerformanceNavigationTiming-secureConnectionStart>
    attribute is now mandatory.**

]]
http://www.w3.org/TR/navigation-timing-2/

The most basic addition has been:
  window.performance.getEntriesByType("navigation")

Yet, looking at implementations around, they all return an empty array, 
instead of an array of size one.

Do we know why we have a slow uptake for the refactored interface?

Philippe