Hentaigana and the Kana Supplement block

[Garth Wallace]

The recent hentaigana proposal requests that they be encoded as
Standardized Variation Sequences of hiragana. This seems like a good
idea, since fallback in the absence of font support would be to the
standard hiragana, so the results would still be readable. But where
does that leave the Kana Supplement block? That block contains only
two encoded characters, but was allocated 256 code points, presumably
for the future encoding of hentaigana. With hentaigana handled by
SVSes, it seems unlikely that many of those points would ever get
filled. I realize there's no shortage of code points in the UCS, but
still.

One thing I noticed: the hentaigana proposal contains a duplicate of
an existing character. MJ090014 (え variant with mother ideograph 江)
looks like it's already encoded in the Kana Supplement block as
U+1B001 HIRAGANA LETTER ARCHAIC YE.