Here is the file found on my KOA2:
Code:
[/var/local/java/prefs] cat language_layer.preferences
#User preferences for LanguageLayer Preferences
#Mon Jun 04 09:40:17 GMT+08:00 2018
pinyin.ftuxShown=true
pinyin.difficulty=1
pinyin.sliderFtuxShown=true
targetLang=zh
dictTimestampcn-kll.zh.pn=1521941647210
pinyin.isVisible=false
dictTimestampcn-kll.en.zh=1528076417459
dictTimestampcn-kll.en.en=1524226765524
dictVersioncn-kll.zh.pn=3.0
dictVersioncn-kll.en.zh=2.0
isEnabled=true
dictVersioncn-kll.en.en=3.0
pinyin.isEnabled=true
As you can see, this file tells kindle where the dict locates, so it can look up the characters in the dict.
I'm still looking for other implementation.