Now that RT-34799 has been fixed, one can get information for non-applied CSS.
However there is still missing information related to lookup.
It is a regression compared to FX 2.2, where we got these information.

Have a look in the test case attached (one zip file for each FX version).
For instance, if you check the information provided for -fx-text-fill, you can see that the lookup information (for -fx-text-base-color) is missing in the FX8 version, while it is provided with the FX2.2 version.