It seems that this camera was made from a 1a/1b, in the 1934/37 years, by the shape of the cover. Probably it was not developped because of the Kodakrome and Agfacolor films, available in 1936 (at least in the West). When did 35 mm colour films appear in FSU countries? It would be interesting to know...
It was certainly too late for such a technique. Probably in 1941 this camera was already in Fed's museum, at Kharkov...
Amazing to discover such a prototype, even on paper. Thanks, Alexander and Vlad!