[HarfBuzz] problems with hmn

[Martin Hosken]

Dear Behdad,

I notice that there are a lot of language tags that are mapped to the internal OT language tag HMN. Given that a bunch of those are Miao languages that have significant stylistic variation in them, I am interested in removing their unification. Do you know where this set of mappings came from (particularly hmd, sfm, etc.)? Is there any chance of removing them or does uniscribe suffer from the same fate?

TIA,
Yours,
Martin