ahhh ! Yes now I understand. I guess Johns intention was to have all the language-specific headerfiles in a subfolder to present the library in a cleaned up order.
With a small loss of oversight to fullfill this library.properties specification the main library-files KeyboardUTF8.h / KeyboardUTF8.cpp should be in src-subfolder and inside this src-subfolder have another subfolder for example "languages" that hold the 206 language-specific headerfiles. I guess "recursive" should be able to crawl down into sub-sub-sub-folders.
@johnwasser : What do you think?
best regards Stefan