Thanks to @2IRS, who pointed here to this thread on the Shiftphone Forum, I just read a post from 12th April 2016 (3 days ago) by Shift-founder Carsten Waldeck.
He asks for “1-2 weeks of patience” and says that documentation about the Shiftphone production would be released in a few days.
I’m looking forward to this documentation, but am sceptic because the past has shown that Shiftphone is rather secretive about their production chain.