This package is meant for macro/package developers: It provides
function-like (fully-expandable) macros that convert a
character code value in one of several Japanese encodings to a
Unicode value. Supported source encodings are: ISO-2022-JP
(jis), EUC-JP (euc), Shift_JIS (sjis), and the Adobe-Japan1
glyph set.

Homepage:
https://ctan.org/pkg/bxjatoucs
