Do the NAV CLOSE simvars work?

Isn’t the simvar NAV CLOSE FREQUENCY supposed to give the frequency of the
closest VOR? And NAV CLOSE LOCALIZER the frequency of the closest ILS
localizer, etc? But if I watch them with the SimvarWatcher program they are
all zero while flying around. (I also tried indexed with 1 or 2, although I
don’t understand what indexing them would mean, and it did not help.) Are they
not yet implemented, or do I misunderstand what they are supposed to tell me?

Hello @tml This request system must be enabled using
NAV1/2/3/4_CLOSE_FREQ_SET event in order to have the CLOSE simvars being
written to. For example, call the NAV1_CLOSE_FREQ_SET passing 1 as an
argument to enable it and then request NAV CLOSE FREQUENCY with index
1 and it will work. Thanks for pointing this out, we will improve the
documentation. Regards, Sylvain