Try the following:
Install the free text editor Notepadd++.
Start it, use the menu Search>-Search in files.
Choose your AddOns folder (read here how to find the folder:
https://www.esoui.com/forums/faq.php..._howto_install)
and search for "Initial gap" (With or without the ").
This is an easy way to see which addon is using the text and then tell the author of this addon via the addon comments page on
www.esoui.com to remove the debug messages please.