Well, that is not a secret at all. The facts are all well communicated and documented in Germany.
Originally Posted by Alpenhause
Their 35mm film has been converted in most cases (there are some exclusions) by German company Photostar / Tura. Excellent, highly skilled employees there (I've been there in the factory). This company is a converting specialist for photographic materials for decades.
Their 120 film has been converted in the past by different companies (depending on the film): Forte, Foma, Fotokemika, Ilford. Currently Foma and Ilford are doing it (if you look at the 120 Rollei Infrared film you will see at once that it is converted by Ilford).
Sheet film converting has been done by German company Banse&Grohmann / Wephota http://wephota.de/ . Also a company with excellent reputation in converting sheet film and paper.