And I also added a link to another Github page :
https://github.com/Mavireck/Kobo-Python-OSKandUtils
It includes the source for the on-screen-keyboard and for useful functions:
A function which draw a message popup (to answer yes/no questions for instance)
A function which draw a textbox popup (to answer a more advanced question)
I think it may be useful for people who write scripts with no GUI : it can make them work without the need to telnet or ssh to answer questions through the shell.