You are looking in the wrong menu.

If / when you look for a script-fu.scm (or a plugin) menu location, use Help -> Plugin Browser
Then enter a search term, usually part of the script name. This for Logo Toolbox.



That tells me Logo Toolbox registers in two places. The one shown is Filters -> Alpha-to-Logo and the other is the File -> Create menu system.

and does it work ? It does here:

The second registration is in the same Logo Toolbox script. It contains the two versions.
First version in the Filters menu and the second version, where you enter text into the script.
That one is in the File -> Create -> Logos menu.



It is possible to change the menu locations by editing the script, but my explanations are shot today. I will leave that explanation to someone else.