Searching the Web I stumbled over a few development projects for the Kobo.
Sadly my knowledge of the language is almost non-existent and translation software is rather limited. :P
As far as I can understand it, this project is similar to our kobo Tweaks plugin, with a few other options, like setting a login password.
It is official only supporting firmware version 2.3-2.4 but seems to run on 2.5 with a few problems.
I hope someone who can read Japanese, might help the rest of us figure out whats going on there. *g*
CFW wiki page