This repository redistributes the internationalized version of Geographic Resources Analysis Support System (GRASS i18n) which used to be distributed at http://www.grass-japan.org/FOSS4G/readme-grass-i18n-ipafonts.eucjp.htm. Since the original version was distributed under GNU GPLv2, this redistributed version is also under GPLv2. See LICENSE (which was added by the redistributor as the original version did not include the license document of GPLv2).
Contents in the grass5.0.3_i686-pc-linux-i18n-ipafull-gnu_bin directory are verbatim copies of the original version (i.e. just extracted from the compressed archive).
You can download the original compressed archive file from the release page.