Where are Config Files (or equivalent) of Bindings?

First off, sorry for this probably quite simple question.

I had a problem with my Gardena Binding which was solved here. The author works in, what I assume to be, Config files of some sort. When looking at the binding overview, I couldn’t see them anywhere. Also when I looked through my rpi4, I couldn’t find them.

Where are these files?

Thanks a lot!

The Items file(s) referred to in that post have nothing particularly to do with the binding.
If you define your Items via GUI, you probably have no Items files nor do you need them.

The %d referred to is part of the Item’s state description. For a UI defined Item in OH3 you would look into its metadata for the ‘pattern’ element.