[XeTeX] font selection debugging

[Vladimir Volovich]

"VV" == Vladimir Volovich writes:

 VV> what is the reason for different font pickup? how can it be
 VV> debugged?

i tried setting FC_DEBUG=5 env.var. but got no useful debugging info from
\font calls (i see debugging info on the first call to \font, showing
how fontconfig reads available fonts, but no debugging for font matching
at all, and subsequent \font calls show no debugging info whatsoever).

Best,
v.