Looking at the language archive, I find U17 only, so I don't know where he finds it.
Don't know why he didn't share it.
The objective of this mod, on the one hand, is to help people with their edits and, on the other hand, to share with the community the discoveries we can make in order to make other people's lives easier.
As I'm not a programmer, the changes I make are always based on trial and error and file comparison.
I believe that the collaboration of people with programming skills could take this mod to another level.