I don't think there is an *.ini file for Touch Screen Setup. The way to do it in the current ver. 1.0.14 is:

Open the Windows registry (Regedit)
Drill down to \Hkey_Current_User\Software\Marantz\Touch Screen Setup\1.0.14\Settings
Change the setting under the 'developer' key from 0 to 1.
Then lastly, close Regedit.

Developer mode enables you to set a name or label for learned or discrete codes instead of using the default "(C)Learned" label. If you want to take advantage of this feature, you need to name the code at the time you "Set IR". It won't let you simply rename an already learned action item. As a work-around, you can copy the learned code and re-paste as a new action by:
Double-click the (C)Learned action item,
Click View IR,
Highlight the entire code and "copy" it by right-mouse clicking on the highlighted area and then clicking "Copy" or you can use Ctrl+C on the keyboard,
Click Cancel
Delete the action item that you just copied the code for,
Click the Set IR button,
Click the Advanced button,
Click OK,
Click View IR button,
Delete the short code in the box,
Paste the code you first copied (Ctrl V),
Click the Label button (now says RC5 0 0),
Type in your new name/description,
Click OK,
Click OK.

This may not be useful to you at all. I'm not aware of anything else Developer mode enables you to do.