What's wrong on this sentence? AFAIK there are only Hashes stored. I think @daniele_athome anwered this (old) question
But I know what you mean Hashes of Phonenumbers not really secure.
@abika you know much more about this tecnical things. Maybe you can find a better description.
If not, feel free to remove this sentence on your own
About the Homepage of the desktop wiki.
I also think it's fine.
I will to the Developers FAQ also add a linked question list like on the "normal" FAQ page as soon as possible.