Hanja Tool enables you to add (and delete) entries to your own Hangul-Hanja dictionary extension, thus expanding and controlling your Hanja choices in Hangul-Hanja conversion mode. The system-wide Hangul-Hanja dictionary is read-only and consequently not editable.
A Hanja Tool is a viewer for the Hangul-Hanja dictionary, which is in binary format and consequently not otherwise readable.
A Hanja Tool creates your own local Hangul-Hanja dictionary in $HOME/.usrhjd. Hanja Tool makes this an extension to the read-only, system-wide Hangul-Hanja dictionary, /usr/lib/mle/ko/syshjd or /usr/lib/mle/ko.UTF-8/syshjd. Each user's dictionary for Hangul-Hanja conversion mode comprises both the system-wide dictionary and the user's own extension, which work seamlessly together.