Neil Hodgson writes:
While I don't have Excel to test with, OpenOffice.org Calc will display in Arabic or Han numerals using the NatNum format codes.
Display is different from input, but at least this is concrete evidence.
Will it accept Arabic on input? (Han might be too much to ask for since Unicode considers Han digits to be "impure".)
Ditto Arabic, I would imagine; ISO 8859/6 (aka Latin/Arabic) does not contain the Arabic digits that have been presented here earlier AFAICT.
DOS code page 864 does use 0xB0-0xB9
OK, Microsoft thought it would be useful.
I'd still like to know whether people actually use them for input (or output, for that matter -- anybody have a corpus of Arabic Form 10-Ks to grep through?), but that's more concrete evidence than we've seen before. Thank you!