/usr/share/ibus-mozc/katakana_half.png is in ibus-mozc 2.19.2623.102+dfsg-1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/ibus-mozc/../icons/mozc/ui-katakana_half.png
/usr/share/ibus-mozc/../icons/mozc/ui-katakana_half.png