[XeTeX] discovering script support

[maxwell]

Is there a program (preferably a command-line program) that will tell me 
what scripts an OpenType font supports?  The 2016 fontspec is giving me 
a warning where I wasn't getting one before, e.g.
     * fontspec warning: "script-not-exist"
     * Font 'Nikosh' does not contain script 'Bengali'.
I've tried fc-list --verbose (including fonts that I know have script 
info), but afaict fc-list does not display script info.  I've tried 
googling this question, but the word "script" seems to be generic enough 
that I can't find anything useful.  There are plenty of hits with "does 
not contain script", but not afaict any that tell me how to determine 
what scripts a font supports.

It may of course be possible that this font supports the Bengali script, 
but doesn't explicitly say that.  But it makes me uneasy...

    Mike Maxwell