If you experience an issue with your install or with the location of your library content, a member of the Spitfire support team may ask for various files to help in resolving the issue. Fortunately enough, these can easily be found from the Troubleshooting tab in the Spitfire App's settings.
From there, you will be able to access the location of three types of files by clicking "show file"
When The Issue You're Experiencing Is With The Spitfire App
Not to worry, the three files above can also be found in the following locations:
Mac
MacHD/Users/[username]/Music/Spitfire Audio/Settings
Windows
C:/Users/[username]/AppData/Roaming/Spitfire Audio/Settings
Note: The above location is hidden by default. Instruction on accessing this location is available here