User dictionary cache
User dictionary is a very handy feature in most mobile devices. This is used to allow your keyboard to remember frequently typed words. When we type a specific word into the keyboard, it automatically provides some suggestions. Android also has this feature and it stores frequently used words in a file named user_dict.db. So developers must be cautious when developing applications. If sensitive information typed into the Android app is allowed to be cached, this data can be accessed by anyone by exploring the user_dict.db file on your device or by using its content provider URI.
Since the user dictionary is accessible by any application using the user dictionary app's content provider, it's trivial for someone to read it and glean interesting information.