Since Royal TSX is a document based application, most user-generated content is stored inside separate documents which have to be saved to a specific location on the file system.
You, the user, specify the location of a document when saving it for the first time or when using "Save Document As...". If you're missing one of your documents, this KB article should help you locate it.

All other settings, preferences and any objects that live in the "Application" document are stored in a predefined container in the user's home directory.
The root directory for these settings is ~/Library/Application Support/Royal TSX
Please note that the "~" character refers to your user's home directory which translates to /Users/YourUserName/.
Please also note that, by default, the Library folder is hidden in Finder. The easiest way to navigate to hidden folders is to use Finder's "Go - Go to Folder..." main menu item and paste the path there.

Here's a short explanation of what each of the files and subdirectories in this folder are used for:

  • UserPreferences.config
    ~/Library/Application Support/Royal TSX/UserPreferences.config
    Stores Preferences, Settings and the content of the "Application Document".
  • License.xml
    ~/Library/Application Support/Royal TSX/License.xml
    Stores your Royal TSX license information (if registered).
    Note: Starting with Royal TSX 4.1.2 you can place your license file in the system folder /Library/Application Support/Royal TSX to make the license available to all users on the machine.
  • AutoStartFiles
    ~/Library/Application Support/Royal TSX/AutoStartFiles/
    Used to store references to the documents that were open when the application was closed the last time. These references are used to re-open documents on the next application start.
  • CrashLogs
    ~/Library/Application Support/Royal TSX/CrashLogs/
    Used to store crash logs. This directory is scanned on every application start and the Crash Reporter will pop up if at least one crash log is found.
  • Logs
    ~/Library/Application Support/Royal TSX/Logs/
    Stores log files created by the application. You can enable File Logging by going to Preferences - Logging - File Logging.
  • Plugins
    ~/Library/Application Support/Royal TSX/Plugins/
    Contains several subdirectories which are used to store installed plugins and their settings.

    • Installed
      ~/Library/Application Support/Royal TSX/Plugins/Installed/
      As the name suggests, installed plugins are stored in this directory.
    • Settings
      ~/Library/Application Support/Royal TSX/Plugins/Settings/
      Used to store plugin-specific settings.
    • WaitingForInstall
      ~/Library/Application Support/Royal TSX/Plugins/WaitingForInstall/
      When a plugin is being installed or updated, it will be transferred to this directory until the application is restarted. The plugin is then, upon successful inititialization being copied over to the "Installed" directory.
    • WaitingForUninstall
      ~/Library/Application Support/Royal TSX/Plugins/WaitingForUninstall/
      When a plugin is being uninstalled, a reference to it will be created in this directory. When the application is restarted, Royal TSX tries to resolve these references to installed plugins which are then in turn being deleted from the "Installed" directory.

  • RecentFiles
    ~/Library/Application Support/Royal TSX/RecentFiles/
    Used to store references to recently used documents. These references are resolved and displayed when using File - Open Recent Document
  • Settings
    ~/Library/Application Support/Royal TSX/Settings/
    Used to store additional settings.
    • Documents
      ~/Library/Application Support/Royal TSX/Settings/Documents/
      Used to store user-specific settings (Favorites/Folder State) of documents. User specific settings need to be enabled on a per-document basis.

There's an additional file located at ~/Library/Preferences/com.lemonmojo.RoyalTSX.App.plist which contains several non-critical settings, like the last time an update check was done.

While you can delete this file using the Finder, macOS seems to cache it somewhere and restores it the next time you start Royal TSX. If you want to reset your settings, it's advisable to use the following command in a terminal window: "defaults delete com.lemonmojo.RoyalTSX.App".