JK Japan Keyboard Helper

It offers you can input Japan words without the physical keyboard. http://project.kimx.info/2016/11/jk-keyboard.html

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manifest.json

{
  "update_url": "https://clients2.google.com/service/update2/crx",
  "default_locale": "en",
  "manifest_version": 3,
  "name": "__MSG_extName__",
  "description": "__MSG_extDesc__",
  "version": "3.3",
  "permissions": [
    "storage"
  ],
  "action": {
    "default_popup": "popup.html",
    "default_icon": {
      "16": "img/icon-128.png",
      "48": "img/icon-128.png",
      "128": "img/icon-128.png"
    }
  }
}