Fade In stores some information in a special folder on your computer. This includes things like dictionary files, templates, autosave backups, shortcut key mappings, system reports, and other things (but not document files).
Press the Windows key, then R to show the Run window. Then type:
and hit Enter. That will bring up an Explorer window with a number of folders in it. One of them will be called Fade In. Double-click on that.
Note: %APPDATA% is a shortcut for C:\Users\<Username>\AppData\Roaming.
From the Finder, choose Go > Go To Folder, and type:
~/Library/Application Support/Fade In (don't forget the leading "~")
For the Mac App Store version you'll need to type:
~/Library/Containers/com.generalcoffee.fadein/Data/Library/Application Support/Fade In
~/.fadeinTags: backup, dictionaries, logging, shortcut keys, troubleshooting