How to refer to a built-in Android drawable color in XML

Without looking things up I don’t know when this changed, but ... to refer to a built-in Android color with the android:drawable XML tag, use code like this:

<item android:state_activated="true" android:drawable="@android:color/darker_gray" />
<item android:state_checked="true" android:drawable="@android:color/background_dark" />

From what I’ve seen there used to be a drawable syntax different than @android:color/darker_gray, but I can confirm that this syntax works with Android 5.